Objects and Types. COMS W1007 Introduction to Computer Science. Christopher Conway 29 May 2003


 Augustus Bruno Gordon
 4 years ago
 Views:
Transcription
1 Objects and Types COMS W1007 Introduction to Computer Science Christopher Conway 29 May 2003
2 Java Programs A Java program contains at least one class definition. public class Hello { public static void main(string[] args) { System.out.println("Hello, world!") ; } } This code defines a class named Hello. The definition of Hello must be in a file Hello.java. The method main is the code that runs when you call java Hello.
3 Identifiers When we give an element in a program a name, we call that name an identifier. In the previous example, Hello was an identifier. In Java, identifiers: Always start with a letter. Can include letters, digits, underscore ( ) and the dollar sign symbol ($). Must be different from any Java reserved words (or keywords). Keywords that we ve seen so far include: public, static, class and void.
4 Case Sensitivity Identifiers and keywords in Java are case sensitive. In other words, capitalization matters. Keywords are always in lowercase. The following identifers are all different: foobar Foobar FooBar FOOBAR Even so, it would probably be a bad idea to use more than one of them in the same program.
5 Whitespace We use the word whitespace to describe blanks, tabs and newline characters. The Java compiler ignores whitespace except when it is used to separate words. E.g.: y=m*x+b;total=total+y; Is the same as: y = m*x + b ; total = total + y ; But which is easier to read?
6 Comments To make our code understandable to those who come after us, we comment sections whose purpose is not immediately obvious. // this comment ends at a newline /* this comment goes until it is explicitly ended with a: */ The Java compiler treats comments as if they were whitespace it ignores them unless they separate words. I.e., foo/*hi, mom!*/bar becomes foo bar, not foobar.
7 Variables A variable is a location in memory where data is stored. Every variable is associated with an identifier. We can assign a value to a variable using the assignment operator =. x = 12 ; The assignment operator means take the value on the righthand side and store it in the memory location on the lefthand side.
8 Types The values a variable can take on and the operations that can be performed on it are determined by its type. Java has five categories of types: Booleans Characters Integers Floatingpoint numbers References to objects
9 Booleans Boolean variables can only take on the values true or false. They are often used to test for conditions in a program. boolean t = true ; boolean f = false ;
10 Characters Character variables can store one character. A character value is a character surrounded by single quotes: char q = Q ; Some special characters are: \n newline \t tab \ single quote \" double quote \\ backslash
11 Integers The integers are the infinite set: Z = {..., 1, 0, 1,... }. Obviously, we can t represent all of the integers in one variable. We have to choose an nbit encoding that can represent 2 n integers. The Java integer types represent both positive and negative integers. An nbit integer x can represent the range: 2 n 1 x < 2 n 1
12 Integers Types The Java integer types are: byte short int long 8 bits 16 bits 32 bits 64 bits E.g.: byte b = 127 ; short s = ; int i = 2 ;
13 Integer Literals An integer value, or literal, can be written in decimal, hex or octal (base8): A hex literal starts with 0x, e.g.: 0x1F (= ) An octal literal starts with just 0, e.g.: 072 (= ) A decimal literal is just a regular number that doesn t start with 0, e.g.: 123 Integer literals are by default of type int. A long literal ends with L.
14 Integer Conversions If an int literal is small enough to fit into a byte or a short, it will be automatically converted. The same is true for long literals and int, byte and short. byte b = 0x7F ; /* 7 bits, OK */ short s = 0x7FFF ; /* 15 bits, OK */ int i = 0x L /* 29 bits, OK */ byte b2 = 0xFF ; /* Error: 255 > 127 */ int i2 = 0x ABCDEFL /* Error: way too big, 57 bits */
15 Integer Conversions: 2 If a literal is too big for its target variable, you must explicitly convert it using a type cast. The number is converted by truncating the extra bits, which is probably not what you want. /* 0x100 = 256 */ byte b = (byte) 0x100 ; /* b now equals 0! */ An int literal can always be assigned to a long variable its value will be the same as if it was assigned to an int variable.
16 FloatingPoint Numbers Floatingpoint numbers are used to represent the reals (R), i.e., numbers that may have fractional parts. The floatingpoint representation uses a form of scientific notation: = = = =
17 FloatingPoint Types A floatingpoint variable uses some of its bits to store the exponent and some of them to store the fractional part (or significand). Thus, floatingpoint numbers are constrained by both magnitude and precision. The Java floatingpoint types are: float double 32 bits 64 bits
18 FloatingPoint Literals Floatingpoint literals are decimal numbers with an optional decimal point You may also include an exponent n, which multiplies the literal by 10 n : 1.234e2 9.9e1 55e0.02e1 A floatingpoint literal is by default of type double. A float literal ends with F.
19 FloatingPoint Conversions The only automatic conversion between floatingpoint types is the assignment of a float value to a double. double d = 1.23F ; /* OK */ float f = 5.99 ; /* Error: cannot assign double to float */ When an integer literal is assigned to a floatingpoint type, it is automatically promoted to floatingpoint, even if that means a loss of precision. float f = 2 ; /* OK, f = 2.0 */ float f2 = L ; /* OK, but f2 = */
20 Objects You may have heard that Java is an objectoriented programming language. What does that mean? An object is a collection of data and operations that manipulate that data. public class Circle { int x ; int y ; double radius ;... }
21 ObjectOriented Programming In objectoriented programming (or OOP), we try to define all of our data as objects, and we define the program as interaction between those objects. public class HappyFace { Circle head ; SemiCircle smile ; } void draw() { head.draw() ; smile.draw() ; }...
22 ObjectOriented Programming: 2 OOP encourages us to think of objects as modules reusable components. If we have Circle, we can use it to make HappyFace. If we have HappyFace, we can use it to make StickMan. public class StickMan { HappyFace head ; Line body ; Line arm1, arm2 ; Line leg1, leg2 ;... }
23 Defining Object Types An object is usually a noun, a thing. To define an object, we first need to define what kind of a thing it is. In Java, we use the keyword class: public class Car { String make ; int model_year ; Color color ; int max_occupants ;... }
24 Defining Object Types: 2 Now that we ve defined a class, we can create instances of the class (i.e., objects). In order to create an instance, we need to tell Java how to initialize the object. We do this using a constructor. public class Car {... public Car(String mk, int yr, Color c, int max) { make = mk ; model_year = yr ; color = c ; max_occupants = max ; } }
25 Defining Objects Now we can use the keyword new to invoke the constructor and create an instance of the class. We can create any kind of a car we need by changing the parameters to the constructor. Car suv = new Car("Ford Explorer", 1999, Color.BLUE, 5) ; Car mini = new Car("Cooper Mini", 2002, Color.RED, 4) ;
26 The Type of an Object An object s type is its class. A Car variable can only take the value of a Car object, or an object that is compatible with Car. (We ll talk about what it means for an object to be compatible next week.) Car suv = new Car("Ford Explorer", 1999, Color.BLUE, 5) ; Car c = suv ; /* OK: suv is a Car */ StickMan s = suv ; /* Error: suv is not a StickMan */
27 References We said earlier that one of the categories of Java types is references to objects. What is a reference? We said that a variable is a location in memory. When we declare an integer variable x and assign it a value 123, the location in memory set aside for x contains the binary representation of 123. x n + 1 n n 1 true e23
28 References: 2 A variable of an object type is a reference variable. When we declare a Car variable suv, the location in memory set aside for suv contains a reference to the location of the data members of suv. suv n + 1 n n e23 ref X "Ford Explorer" 1999 Color.BLUE 5
29 Reference Assignment Assignment means copy the value on the righthand side into the memory location on the lefthand side. If you assign one variable to another, the value is copied and that is that. int x = 0 ; int y = x ; /* x and y both equal 0 */ x = 2 ; /* x now equals 2, y still equals 0 */
30 Reference Assignment: 2 When you assign the value of one reference variable to another, it s the reference that s copied, not the object. This can lead to surprising results. Point p = new Point(0,0) ; Point q = p ; /* p and q now refer to the same object */ p.x = 2 ; /* p.x now equals 2 q.x now equals 2, as well */
31 Reference Assignment: 2 When you copy the reference value, you still have only one copy of the object data. You just have two references to it. p q 0xFFFFFFFF ref ref false x: 2 y: 0 This may seem confusing at first, but there s a simple reason for it: copying data is slow. We avoid it when we can.
32 Strings String is a class that has special support in Java. A string literal is surrounded by double quotes. String hamlet = "To be or not to be" ; String is a reference type, but you don t have to use the new operator to create an instance. You can assign a string literal to a String variable directly, as above.
33 Strings: 2 Character and string values may seem confusingly similar. A char value is a single character, surrounded by single quotes: char c1 = C ; char c2 = \n ; A String value is a sequence of characters surrounded by double quotes. A String may be empty. String s1 = "C" ; String s2 = "" ; String s3 = "LastName\tFirstName\tGrade\n" ; /* Words separated by tabs, closed with a newline. */
34 Arithmetic Java provides five basic arithmetic operators: + addition  subtraction * multiplication / division % remainder There are also unary + and  operators. The operators can be applied to any of the integer or floatingpoint types.
35 Operator Precedence Multiplication, division and remainder have higher precedence than addition and subtraction. All higherprecedence operators are evaluated before any lowerprecedence operators. Operators at the same precedence are evaluated lefttoright. Parentheses can be used to override operator precedence. x+y*z = x+(y*z) a*b+c%d = (a*b)+(c%d) Assignment is the lowestprecedence operator of all. Unary + and  are higherprecedence than multiplication.
36 Integer Arithmetic Integer division is gradeschool division: fractional results round toward zero. 9/2 = 49/2 = 4 Integer division and remainder obey the rule: (x/y)*y + x%y = x 9%2 = 19%2 = 1
37 Overflow and Underflow If the result of an operation is greater than the maximum value (overflow) or less than the minimum value (underflow) of its type, the result wraps around. Integer.MAX VALUE + 1 = Integer.MIN VALUE Integer.MIN VALUE  1 = Integer.MAX VALUE All arithmetic is performed with int and long values. byte and short values are automatically promoted.
38 Typecasting The result of an integer arithmetic operation is always an int or long. This means you have to cast back to a smaller type when you assign a result. byte b = 1 ; byte b2 = b + 1 ; /* Error: can t assign int to byte */ byte b3 = (byte)( b + 1 ) ; /* OK: b3 now equals 2 */ byte b4 = (byte)( Byte.MAX_VALUE + 1 ) ; /* OK: b4 now equals Byte.MIN_VALUE */
39 Floatingpoint Arithmetic Floatingpoint arithmetic works pretty much how you would expect, except you have to be careful about precision. float f = 1.0e8F, g = 1.0e8F ; float x = f + g ; /* x now equals 1.0e8 */ float y = (f  f) + g ; /* y now equals 1.0e8 */ float z = f  (f + g) ; /* z now equals 0 */
40 Special Floatingpoint Values Floatingpoint arithmetic has several special values that behave in interesting ways. +Inf Inf Infinity +0.0 Zero Negative Infinity 0.0 Negative Zero NaN Not a Number
41 Special Floatingpoint Values: 2 Here s how to get and what you get from, these special values: 1/0.0 = Inf 1/0.0 = Inf 1/Inf = 0.0 1/Inf = 0.0 Inf/Inf = NaN 1+Inf = Inf 1%Inf = 1 Inf*0.0 = NaN 1Inf = Inf Inf%1 = NaN
42 Increment and Decrement Adding or subtracting one from a number is a common operation. Java provides a shorthand in the increment (++) and decrement () operators. Increment and decrement can be used as prefix or postfix operators. In prefix form, increment means add one to this variable and use the incremented value in this expression. In postfix form, increment means add one to this variable, and use the previous value in this expression. Aside: C also has increment and decrement. The developers of C++ wanted to indicate it was an incremental improvement on C.
43 Increment and Decrement: Examples int i = 0, j ; i++ ; /* i = 1 */ i ; /* i = 0 */ j = i++ ; /* i=1, j=0 */ j = ++i ; /* i=2, j=2 */ j = i ; /* i=1, j=1 */ j = i ; /* i=0, j=1 */
44 Increment and Decrement: Precedence Increment and decrement are higherprecedence than any operator we ve seen so far. Postfix is higherprecedence than prefix. Highest Lowest = ++,  (postfix) ++,  (prefix), +,  (unary) *, /, % +, 
45 Comparison Operators Java provides the following operators for comparing numbers: > Greater than < Less than >= Greater than or equal to <= Less than or equal to == Equal to!= Not equal to == and!= can be applied to boolean values, but >, <, >= and <= cannot. The result of a comparison operation is a boolean value.
46 Reference Comparison == and!= can be applied to reference variables. They test whether the references are equal, not the data members. Point x = new Point(0,0) ; Point y = new Point(0,0) ; Point z = x ; boolean b = x==y ; /* false, x and y are references to different objects */ boolean b2 = x==z ; /* true, x and z are references to the same object */
47 The instanceof Operator Occasionally we want to investigate the type of an object. The instanceof operator tells us if a reference variable is an instance of a class. Point x = new Point(0,0) ; boolean a = x instanceof Point ; /* true, x is a Point */ boolean b = x instanceof Car ; /* false, x is not a Car */
48 Comparison Operators: Precedence The relational operators have higher precedence than the equality operators. All of the comparison operators have lower precedence than the arithmetic operators. Highest Lowest = ++,  (postfix) ++,  (prefix), +,  (unary) *, /, % +,  <, >, <=, >=, instanceof ==,!=
49 Logical Operators Java provides the following logical operators: & AND OR ˆ XOR! NOT && shortcircuit AND shortcircuit OR The operands of a logical operator are boolean values and the result is also a boolean.
50 AND AND is true if and only if both of its operands are true. a b a&b false false false false true false true false false true true true
51 OR OR is true if one of its operands are true. a b a b false false false false true true true false true true true true
52 XOR XOR is true if and only if exactly one of its operands is true. a b aˆb false false false false true true true false true true true false
53 NOT NOT inverts its operand. a!a false true true false
54 Shortcircuit AND and OR The logical AND and OR operators ( & and ) always evaluate both of their operands. In some cases, this can be wasteful. If the first operand of AND is false, then AND must be false. Shortcircuit AND ( && ) doesn t evaluate the second operand if the first is false. If the first operand of OR is true, then OR must be true. Shortcircuit OR ( ) doesn t evaluate the second operand if the first is true.
55 Shortcircuit Operators: Example boolean a = true, b = false ; int i = 0, j = 1, k = 2 ; boolean c = a (i=j) < k ; /* c = true, i = 0 */ boolean d = a && (i=j) < k ; /* d = true, i = 1 */ boolean e = a && (i=k) < j ; /* e = false, i = 2 */
56 Logical Operators: Precedence AND has higher precedence than OR. The shortcircuit operators have lower precedence than their ordinary equivalents. All of the logical operators have lower precedence than arithmetic and comparison. Highest Arithmetic, etc. <, >, <=, >=, instanceof ==,!= & ˆ && Lowest =
57 Bitwise Operators Java provides the following operators for manipulating bit patterns: & Bitwise AND Bitwise OR ˆ Bitwise XOR << Shift left >> Shift right signed >>> Shift right unsigned &, and ˆ are overloaded operators. They are logical operators when applied to boolean values, and bitwise operators when applied to integers.
58 Bitwise AND Bitwise AND applies the AND operation to every pair of bits in the operands. A 0 is treated as false and a 1 is treated as true xF6 & 0x93 = AND =
59 Bitwise OR Bitwise OR applies the OR operation to every pair of bits in the operands. 0xF6 0x93 = OR =
60 Bitwise XOR Bitwise XOR applies the XOR operation to every pair of bits in the operands. 0xF6 ˆ 0x93 = XOR =
61 Shift left The shift left operator shifts the bits in its first operand as indicated by its second operand. 0xF6 << 2 = <<
62 Shift right signed The way integers are represented in Java, the highestorder bit is the sign of the number. If we shift right the same way we shift left (bringing in zeroes), the sign might changed. The shift right signed operator brings in bits that match the sign. 0xF6 >> 2 = >>
63 Shift right unsigned The shift right unsigned operator ignores the sign bit and brings in zeroes. 0xF6 >>> 2 = >>>
64 Using Bitwise Operators Bitwise AND is good for turning bits off: int i = 0xC7 & 0xFE ; /* i = 0xC6 */ Bitwise OR is good for turning bits on: int i = 0xC7 0x08 ; /* i = 0xCF */ Bitwise XOR is good for flipping bits: int i = 0xC7 0x09 ; /* i = 0xCE */
65 Bitwise Operators: Precedence The precedence of bitwise AND, OR and XOR match their logical equivalents. The precendence of the shift operators is between the arithmetic and comparison operators. Highest Lowest Unary operators *, /, % +,  <<, >>, >>> <, >, <=, >=, instanceof ==,!= Logical operators, assignment
66 String Concatenation The + is also overloaded. When applied to two strings, it concatenates them. I.e., it appends the second to the first. String a = "Flower" ; String b = "Power" ; String c = a + b ; /* c = "FlowerPower" */
67 String Concatenation: 2 All of the basic types are automatically converted to String under the concatenation operator. int i = 2 ; double x = 5.2 ; String s = "i = " + i + " and x = " + x ; /* s = "i = 2 and x = 5.2" */
68 Assignment Operators All of the binary operators have corresponding compound assignment operators. += %= &= = >>= ˆ= *= <<= = /= >>>= x op= y is equivalent to x = x op y. All of the compound assignment operators have the same precedence as assignment.
A Java program contains at least one class definition.
Java Programs Identifiers Objects and Types COMS W1007 Introduction to Computer Science Christopher Conway 29 May 2003 A Java program contains at least one class definition. public class Hello { public
More informationExpressions and Data Types CSC 121 Spring 2015 Howard Rosenthal
Expressions and Data Types CSC 121 Spring 2015 Howard Rosenthal Lesson Goals Understand the basic constructs of a Java Program Understand how to use basic identifiers Understand simple Java data types
More informationExpressions and Data Types CSC 121 Fall 2015 Howard Rosenthal
Expressions and Data Types CSC 121 Fall 2015 Howard Rosenthal Lesson Goals Understand the basic constructs of a Java Program Understand how to use basic identifiers Understand simple Java data types and
More informationFull file at
Java Programming: From Problem Analysis to Program Design, 3 rd Edition 21 Chapter 2 Basic Elements of Java At a Glance Instructor s Manual Table of Contents Overview Objectives s Quick Quizzes Class
More informationChapter 3: Operators, Expressions and Type Conversion
101 Chapter 3 Operators, Expressions and Type Conversion Chapter 3: Operators, Expressions and Type Conversion Objectives To use basic arithmetic operators. To use increment and decrement operators. To
More informationJAVA Programming Fundamentals
Chapter 4 JAVA Programming Fundamentals By: Deepak Bhinde PGT Comp.Sc. JAVA character set Character set is a set of valid characters that a language can recognize. It may be any letter, digit or any symbol
More informationJAVA OPERATORS GENERAL
JAVA OPERATORS GENERAL Java provides a rich set of operators to manipulate variables. We can divide all the Java operators into the following groups: Arithmetic Operators Relational Operators Bitwise Operators
More informationDeclaration and Memory
Declaration and Memory With the declaration int width; the compiler will set aside a 4byte (32bit) block of memory (see right) The compiler has a symbol table, which will have an entry such as Identifier
More informationJava provides a rich set of operators to manipulate variables. We can divide all the Java operators into the following groups:
Basic Operators Java provides a rich set of operators to manipulate variables. We can divide all the Java operators into the following groups: Arithmetic Operators Relational Operators Bitwise Operators
More informationComputer System and programming in C
1 Basic Data Types Integral Types Integers are stored in various sizes. They can be signed or unsigned. Example Suppose an integer is represented by a byte (8 bits). Leftmost bit is sign bit. If the sign
More informationOperators and Expressions
Operators and Expressions Conversions. Widening and Narrowing Primitive Conversions Widening and Narrowing Reference Conversions Conversions up the type hierarchy are called widening reference conversions
More informationCMPT 125: Lecture 3 Data and Expressions
CMPT 125: Lecture 3 Data and Expressions Tamara Smyth, tamaras@cs.sfu.ca School of Computing Science, Simon Fraser University January 3, 2009 1 Character Strings A character string is an object in Java,
More informationThese are reserved words of the C language. For example int, float, if, else, for, while etc.
Tokens in C Keywords These are reserved words of the C language. For example int, float, if, else, for, while etc. Identifiers An Identifier is a sequence of letters and digits, but must start with a letter.
More informationProgram Fundamentals
Program Fundamentals /* HelloWorld.java * The classic Hello, world! program */ class HelloWorld { public static void main (String[ ] args) { System.out.println( Hello, world! ); } } /* HelloWorld.java
More informationC Language Part 1 Digital Computer Concept and Practice Copyright 2012 by Jaejin Lee
C Language Part 1 (Minor modifications by the instructor) References C for Python Programmers, by Carl Burch, 2011. http://www.toves.org/books/cpy/ The C Programming Language. 2nd ed., Kernighan, Brian,
More informationBASIC COMPUTATION. public static void main(string [] args) Fundamentals of Computer Science I
BASIC COMPUTATION x public static void main(string [] args) Fundamentals of Computer Science I Outline Using Eclipse Data Types Variables Primitive and Class Data Types Expressions Declaration Assignment
More informationTopic Notes: Bits and Bytes and Numbers
Computer Science 220 Assembly Language & Comp Architecture Siena College Fall 2010 Topic Notes: Bits and Bytes and Numbers Binary Basics At least some of this will be review, but we will go over it for
More informationCS5000: Foundations of Programming. Mingon Kang, PhD Computer Science, Kennesaw State University
CS5000: Foundations of Programming Mingon Kang, PhD Computer Science, Kennesaw State University Overview of Source Code Components Comments Library declaration Classes Functions Variables Comments Can
More informationBasics of Java Programming
Basics of Java Programming Lecture 2 COP 3252 Summer 2017 May 16, 2017 Components of a Java Program statements  A statement is some action or sequence of actions, given as a command in code. A statement
More informationData and Variables. Data Types Expressions. String Concatenation Variables Declaration Assignment Shorthand operators. Operators Precedence
Data and Variables Data Types Expressions Operators Precedence String Concatenation Variables Declaration Assignment Shorthand operators Review class All code in a java file is written in a class public
More informationMore Programming Constructs  Introduction
More Programming Constructs  Introduction We can now examine some additional programming concepts and constructs Chapter 5 focuses on: internal data representation conversions between one data type and
More informationThe Arithmetic Operators. Unary Operators. Relational Operators. Examples of use of ++ and
The Arithmetic Operators The arithmetic operators refer to the standard mathematical operators: addition, subtraction, multiplication, division and modulus. Op. Use Description + x + y adds x and y x y
More informationThe Arithmetic Operators
The Arithmetic Operators The arithmetic operators refer to the standard mathematical operators: addition, subtraction, multiplication, division and modulus. Examples: Op. Use Description + x + y adds x
More informationReview: Exam 1. Your First C++ Program. Declaration Statements. Tells the compiler. Examples of declaration statements
Review: Exam 1 9/20/06 CS150 Introduction to Computer Science 1 1 Your First C++ Program 1 //*********************************************************** 2 // File name: hello.cpp 3 // Author: Shereen Khoja
More informationCS102: Variables and Expressions
CS102: Variables and Expressions The topic of variables is one of the most important in C or any other highlevel programming language. We will start with a simple example: int x; printf("the value of
More informationZhengLiang Lu Java Programming 45 / 79
1 class Lecture2 { 2 3 "Elementray Programming" 4 5 } 6 7 / References 8 [1] Ch. 2 in YDL 9 [2] Ch. 2 and 3 in Sharan 10 [3] Ch. 2 in HS 11 / ZhengLiang Lu Java Programming 45 / 79 Example Given a radius
More informationWill introduce various operators supported by C language Identify supported operations Present some of terms characterizing operators
Operators Overview Will introduce various operators supported by C language Identify supported operations Present some of terms characterizing operators Operands and Operators Mathematical or logical relationships
More informationTypes and Expressions. Chapter 3
Types and Expressions Chapter 3 Chapter Contents 3.1 Introductory Example: Einstein's Equation 3.2 Primitive Types and Reference Types 3.3 Numeric Types and Expressions 3.4 Assignment Expressions 3.5 Java's
More informationExpressions and Data Types CSC 121 Spring 2017 Howard Rosenthal
Expressions and Data Types CSC 121 Spring 2017 Howard Rosenthal Lesson Goals Understand the basic constructs of a Java Program Understand how to use basic identifiers Understand simple Java data types
More informationComputer Science 324 Computer Architecture Mount Holyoke College Fall Topic Notes: Bits and Bytes and Numbers
Computer Science 324 Computer Architecture Mount Holyoke College Fall 2007 Topic Notes: Bits and Bytes and Numbers Number Systems Much of this is review, given the 221 prerequisite Question: how high can
More informationTools : The Java Compiler. The Java Interpreter. The Java Debugger
Tools : The Java Compiler javac [ options ] filename.java... depend: Causes recompilation of class files on which the source files given as command line arguments recursively depend. O: Optimizes code,
More informationCOMP2121: Microprocessors and Interfacing. Number Systems
COMP2121: Microprocessors and Interfacing Number Systems http://www.cse.unsw.edu.au/~cs2121 Lecturer: Hui Wu Session 2, 2017 1 1 Overview Positional notation Decimal, hexadecimal, octal and binary Converting
More informationChapter 2 Elementary Programming
Chapter 2 Elementary Programming Part I 1 Motivations In the preceding chapter, you learned how to create, compile, and run a Java program. Starting from this chapter, you will learn how to solve practical
More informationTopic Notes: Bits and Bytes and Numbers
Computer Science 220 Assembly Language & Comp Architecture Siena College Fall 2011 Topic Notes: Bits and Bytes and Numbers Binary Basics At least some of this will be review for most of you, but we start
More informationInf2C  Computer Systems Lecture 2 Data Representation
Inf2C  Computer Systems Lecture 2 Data Representation Boris Grot School of Informatics University of Edinburgh Last lecture Moore s law Types of computer systems Computer components Computer system stack
More informationBasic operators, Arithmetic, Relational, Bitwise, Logical, Assignment, Conditional operators. JAVA Standard Edition
Basic operators, Arithmetic, Relational, Bitwise, Logical, Assignment, Conditional operators JAVA Standard Edition Java  Basic Operators Java provides a rich set of operators to manipulate variables.
More informationCSCI 2010 Principles of Computer Science. Data and Expressions 08/09/2013 CSCI
CSCI 2010 Principles of Computer Science Data and Expressions 08/09/2013 CSCI 2010 1 Data Types, Variables and Expressions in Java We look at the primitive data types, strings and expressions that are
More informationInformation Science 1
Information Science 1 Simple Calcula,ons Week 09 College of Information Science and Engineering Ritsumeikan University Topics covered l Terms and concepts from Week 8 l Simple calculations Documenting
More informationECE 122 Engineering Problem Solving with Java
ECE 122 Engineering Problem Solving with Java Lecture 3 Expression Evaluation and Program Interaction Outline Problem: How do I input data and use it in complicated expressions Creating complicated expressions
More informationCOMP2611: Computer Organization. Data Representation
COMP2611: Computer Organization Comp2611 Fall 2015 2 1. Binary numbers and 2 s Complement Numbers 3 Bits: are the basis for binary number representation in digital computers What you will learn here: How
More informationVariables and literals
Demo lecture slides Although I will not usually give slides for demo lectures, the first two demo lectures involve practice with things which you should really know from G51PRG Since I covered much of
More informationGO  OPERATORS. This tutorial will explain the arithmetic, relational, logical, bitwise, assignment and other operators one by one.
http://www.tutorialspoint.com/go/go_operators.htm GO  OPERATORS Copyright tutorialspoint.com An operator is a symbol that tells the compiler to perform specific mathematical or logical manipulations.
More informationJava Programming Fundamentals. Visit for more.
Chapter 4: Java Programming Fundamentals Informatics Practices Class XI (CBSE Board) Revised as per CBSE Curriculum 2015 Visit www.ip4you.blogspot.com for more. Authored By: Rajesh Kumar Mishra, PGT (Comp.Sc.)
More information3. Java  Language Constructs I
Educational Objectives 3. Java  Language Constructs I Names and Identifiers, Variables, Assignments, Constants, Datatypes, Operations, Evaluation of Expressions, Type Conversions You know the basic blocks
More informationSOFTWARE DEVELOPMENT 1. Operators 2018W A. Ferscha (Institute of Pervasive Computing, JKU Linz)
SOFTWARE DEVELOPMENT 1 Operators 2018W (Institute of Pervasive Computing, JKU Linz) OPERATORS Operators are required to form expressions. Depending on the number of operands they take, they are called:
More informationExpressions and Casting
Expressions and Casting C# Programming Rob Miles Data Manipulation We know that programs use data storage (variables) to hold values and statements to process the data The statements are obeyed in sequence
More informationProgramming in C++ 5. Integral data types
Programming in C++ 5. Integral data types! Introduction! Type int! Integer multiplication & division! Increment & decrement operators! Associativity & precedence of operators! Some common operators! Long
More informationLanguage Basics. /* The NUMBER GAME  User tries to guess a number between 1 and 10 */ /* Generate a random number between 1 and 10 */
Overview Language Basics This chapter describes the basic elements of Rexx. It discusses the simple components that make up the language. These include script structure, elements of the language, operators,
More informationFundamentals of Programming
Fundamentals of Programming Lecture 3  Constants, Variables, Data Types, And Operations Lecturer : Ebrahim Jahandar Borrowed from lecturer notes by Omid Jafarinezhad Outline C Program Data types Variables
More informationGetting started with Java
Getting started with Java Magic Lines public class MagicLines { public static void main(string[] args) { } } Comments Comments are lines in your code that get ignored during execution. Good for leaving
More informationUNIT 3 Introduction to C++
UNIT 3 Introduction to C++ C++ Character Sets: Letters AZ, az Digits 09 Special Symbols Space +  * / ^ \ ( ) [ ] =!= . $, ; : %! &? _ # = @ White Spaces Blank spaces, horizontal tab, carriage
More informationFundamental of Programming (C)
Borrowed from lecturer notes by Omid Jafarinezhad Fundamental of Programming (C) Lecturer: Vahid Khodabakhshi Lecture 3 Constants, Variables, Data Types, And Operations Department of Computer Engineering
More informationLe L c e t c ur u e e 2 To T p o i p c i s c t o o b e b e co c v o e v r e ed e Variables Operators
Course Name: Advanced Java Lecture 2 Topics to be covered Variables Operators Variables Introduction A variables can be considered as a name given to the location in memory where values are stored. One
More informationSECTION II: LANGUAGE BASICS
Chapter 5 SECTION II: LANGUAGE BASICS Operators Chapter 04: Basic Fundamentals demonstrated declaring and initializing variables. This chapter depicts how to do something with them, using operators. Operators
More informationCS113: Lecture 3. Topics: Variables. Data types. Arithmetic and Bitwise Operators. Order of Evaluation
CS113: Lecture 3 Topics: Variables Data types Arithmetic and Bitwise Operators Order of Evaluation 1 Variables Names of variables: Composed of letters, digits, and the underscore ( ) character. (NO spaces;
More informationA variable is a name for a location in memory A variable must be declared
Variables A variable is a name for a location in memory A variable must be declared, specifying the variable's name and the type of information that will be held in it data type variable name int total;
More information4 Programming Fundamentals. Introduction to Programming 1 1
4 Programming Fundamentals Introduction to Programming 1 1 Objectives At the end of the lesson, the student should be able to: Identify the basic parts of a Java program Differentiate among Java literals,
More informationObject oriented programming. Instructor: Masoud Asghari Web page: Ch: 3
Object oriented programming Instructor: Masoud Asghari Web page: http://www.masses.ir/lectures/oops2017sut Ch: 3 1 In this slide We follow: https://docs.oracle.com/javase/tutorial/index.html Trail: Learning
More informationCharacter Set. The character set of C represents alphabet, digit or any symbol used to represent information. Digits 0, 1, 2, 3, 9
Character Set The character set of C represents alphabet, digit or any symbol used to represent information. Types Uppercase Alphabets Lowercase Alphabets Character Set A, B, C, Y, Z a, b, c, y, z Digits
More informationCOMP Primitive and Class Types. Yi Hong May 14, 2015
COMP 110001 Primitive and Class Types Yi Hong May 14, 2015 Review What are the two major parts of an object? What is the relationship between class and object? Design a simple class for Student How to
More informationData and Expressions. Outline. Data and Expressions 12/18/2010. Let's explore some other fundamental programming concepts. Chapter 2 focuses on:
Data and Expressions Data and Expressions Let's explore some other fundamental programming concepts Chapter 2 focuses on: Character Strings Primitive Data The Declaration And Use Of Variables Expressions
More informationReserved Words and Identifiers
1 Programming in C Reserved Words and Identifiers Reserved word Word that has a specific meaning in C Ex: int, return Identifier Word used to name and refer to a data element or object manipulated by the
More informationSlide 1 CS 170 Java Programming 1 Expressions Duration: 00:00:41 Advance mode: Auto
CS 170 Java Programming 1 Expressions Slide 1 CS 170 Java Programming 1 Expressions Duration: 00:00:41 What is an expression? Expression Vocabulary Any combination of operators and operands which, when
More informationVisual C# Instructor s Manual Table of Contents
Visual C# 2005 21 Chapter 2 Using Data At a Glance Instructor s Manual Table of Contents Overview Objectives s Quick Quizzes Class Discussion Topics Additional Projects Additional Resources Key Terms
More informationObjectives. Chapter 2: Basic Elements of C++ Introduction. Objectives (cont d.) A C++ Program (cont d.) A C++ Program
Objectives Chapter 2: Basic Elements of C++ In this chapter, you will: Become familiar with functions, special symbols, and identifiers in C++ Explore simple data types Discover how a program evaluates
More informationCEN 414 Java Programming
CEN 414 Java Programming Instructor: H. Esin ÜNAL SPRING 2017 Slides are modified from original slides of Y. Daniel Liang WEEK 2 ELEMENTARY PROGRAMMING 2 Computing the Area of a Circle public class ComputeArea
More informationExpressions and Casting. Data Manipulation. Simple Program 11/5/2013
Expressions and Casting C# Programming Rob Miles Data Manipulation We know that programs use data storage (variables) to hold values and statements to process the data The statements are obeyed in sequence
More informationChapter 2: Basic Elements of C++
Chapter 2: Basic Elements of C++ Objectives In this chapter, you will: Become familiar with functions, special symbols, and identifiers in C++ Explore simple data types Discover how a program evaluates
More informationOperators. Java operators are classified into three categories:
Operators Operators are symbols that perform arithmetic and logical operations on operands and provide a meaningful result. Operands are data values (variables or constants) which are involved in operations.
More informationChapter 2: Basic Elements of C++ Objectives. Objectives (cont d.) A C++ Program. Introduction
Chapter 2: Basic Elements of C++ C++ Programming: From Problem Analysis to Program Design, Fifth Edition 1 Objectives In this chapter, you will: Become familiar with functions, special symbols, and identifiers
More informationDEPARTMENT OF MATHS, MJ COLLEGE
T. Y. B.Sc. Mathematics MTH 356 (A) : Programming in C Unit 1 : Basic Concepts Syllabus : Introduction, Character set, C token, Keywords, Constants, Variables, Data types, Symbolic constants, Over flow,
More informationWork relative to other classes
Work relative to other classes 1 Hours/week on projects 2 C BOOTCAMP DAY 1 CS3600, Northeastern University Slides adapted from Anandha Gopalan s CS132 course at Univ. of Pittsburgh Overview C: A language
More informationUnit 3. Operators. School of Science and Technology INTRODUCTION
INTRODUCTION Operators Unit 3 In the previous units (unit 1 and 2) you have learned about the basics of computer programming, different data types, constants, keywords and basic structure of a C program.
More informationChapter 2 Working with Data Types and Operators
JavaScript, Fourth Edition 21 Chapter 2 Working with Data Types and Operators At a Glance Instructor s Manual Table of Contents Overview Objectives Teaching Tips Quick Quizzes Class Discussion Topics
More informationPrimitive Data Types: Intro
Primitive Data Types: Intro Primitive data types represent single values and are built into a language Java primitive numeric data types: 1. Integral types (a) byte (b) int (c) short (d) long 2. Real types
More information2 nd Week Lecture Notes
2 nd Week Lecture Notes Scope of variables All the variables that we intend to use in a program must have been declared with its type specifier in an earlier point in the code, like we did in the previous
More informationCSE 1001 Fundamentals of Software Development 1. Identifiers, Variables, and Data Types Dr. H. Crawford Fall 2018
CSE 1001 Fundamentals of Software Development 1 Identifiers, Variables, and Data Types Dr. H. Crawford Fall 2018 Identifiers, Variables and Data Types Reserved Words Identifiers in C Variables and Values
More informationSir Muhammad Naveed. Arslan Ahmed Shaad ( ) Muhammad Bilal ( )
Sir Muhammad Naveed Arslan Ahmed Shaad (1163135 ) Muhammad Bilal ( 1163122 ) www.techo786.wordpress.com CHAPTER: 2 NOTES: VARIABLES AND OPERATORS The given Questions can also be attempted as Long Questions.
More informationLecture 3. More About C
Copyright 1996 David R. Hanson Computer Science 126, Fall 1996 31 Lecture 3. More About C Programming languages have their lingo Programming language Types are categories of values int, float, char Constants
More informationMore about Binary 9/6/2016
More about Binary 9/6/2016 Unsigned vs. Two s Complement 8bit example: 1 1 0 0 0 0 1 1 2 7 +2 6 + 2 1 +2 0 = 128+64+2+1 = 1952 7 +2 6 + 2 1 +2 0 = 128+64+2+1 = 61 Why does two s complement work this
More informationCS61B Lecture #14: Integers. Last modified: Wed Sep 27 15:44: CS61B: Lecture #14 1
CS61B Lecture #14: Integers Last modified: Wed Sep 27 15:44:05 2017 CS61B: Lecture #14 1 Integer Types and Literals Type Bits Signed? Literals byte 8 Yes Cast from int: (byte) 3 short 16 Yes None. Cast
More informationCOSC 243. Data Representation 3. Lecture 3  Data Representation 3 1. COSC 243 (Computer Architecture)
COSC 243 Data Representation 3 Lecture 3  Data Representation 3 1 Data Representation Test Material Lectures 1, 2, and 3 Tutorials 1b, 2a, and 2b During Tutorial a Next Week 12 th and 13 th March If you
More informationCHAPTER 3 Expressions, Functions, Output
CHAPTER 3 Expressions, Functions, Output More Data Types: Integral Number Types short, long, int (all represent integer values with no fractional part). Computer Representation of integer numbers  Number
More informationChapter 4. Operations on Data
Chapter 4 Operations on Data 1 OBJECTIVES After reading this chapter, the reader should be able to: List the three categories of operations performed on data. Perform unary and binary logic operations
More informationOperators in java Operator operands.
Operators in java Operator in java is a symbol that is used to perform operations and the objects of operation are referred as operands. There are many types of operators in java such as unary operator,
More informationDaMPL. Language Reference Manual. Henrique Grando
DaMPL Language Reference Manual Bernardo Abreu Felipe Rocha Henrique Grando Hugo Sousa bd2440 flt2107 hp2409 ha2398 Contents 1. Getting Started... 4 2. Syntax Notations... 4 3. Lexical Conventions... 4
More informationFundamental Data Types. CSE 130: Introduction to Programming in C Stony Brook University
Fundamental Data Types CSE 130: Introduction to Programming in C Stony Brook University Program Organization in C The C System C consists of several parts: The C language The preprocessor The compiler
More informationLexical Considerations
Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.035, Fall 2005 Handout 6 Decaf Language Wednesday, September 7 The project for the course is to write a
More informationCS 31: Introduction to Computer Systems. 03: Binary Arithmetic January 29
CS 31: Introduction to Computer Systems 03: Binary Arithmetic January 29 WiCS! Swarthmore Women in Computer Science Slide 2 Today Binary Arithmetic Unsigned addition Subtraction Representation Signed magnitude
More informationInformation Science 1
Topics covered Information Science 1 Terms and concepts from Week 8 Simple calculations Documenting programs Simple Calcula,ons Expressions Arithmetic operators and arithmetic operator precedence Mixedtype
More informationCS 115 Data Types and Arithmetic; Testing. Taken from notes by Dr. Neil Moore
CS 115 Data Types and Arithmetic; Testing Taken from notes by Dr. Neil Moore Statements A statement is the smallest unit of code that can be executed on its own. So far we ve seen simple statements: Assignment:
More informationNumerical computing. How computers store real numbers and the problems that result
Numerical computing How computers store real numbers and the problems that result The scientific method Theory: Mathematical equations provide a description or model Experiment Inference from data Test
More informationOperators. Java Primer Operators1 Scott MacKenzie = 2. (b) (a)
Operators Representing and storing primitive data types is, of course, essential for any computer language. But, so, too, is the ability to perform operations on data. Java supports a comprehensive set
More informationProgramming Lecture 3
Programming Lecture 3 Expressions (Chapter 3) Primitive types Aside: Context Free Grammars Constants, variables Identifiers Variable declarations Arithmetic expressions Operator precedence Assignment statements
More informationNumerical Data. CS 180 Sunil Prabhakar Department of Computer Science Purdue University
Numerical Data CS 180 Sunil Prabhakar Department of Computer Science Purdue University Problem Write a program to compute the area and perimeter of a circle given its radius. Requires that we perform operations
More informationFloatingPoint Data Representation and Manipulation 198:231 Introduction to Computer Organization Lecture 3
FloatingPoint Data Representation and Manipulation 198:231 Introduction to Computer Organization Instructor: Nicole Hynes nicole.hynes@rutgers.edu 1 Fixed Point Numbers Fixed point number: integer part
More informationC OVERVIEW BASIC C PROGRAM STRUCTURE. C Overview. Basic C Program Structure
C Overview Basic C Program Structure C OVERVIEW BASIC C PROGRAM STRUCTURE Goals The function main( )is found in every C program and is where every C program begins speed execution portability C uses braces
More informationMODULE 02: BASIC COMPUTATION IN JAVA
MODULE 02: BASIC COMPUTATION IN JAVA Outline Variables Naming Conventions Data Types Primitive Data Types Review: int, double New: boolean, char The String Class Type Conversion Expressions Assignment
More informationProgramming for Engineers Introduction to C
Programming for Engineers Introduction to C ICEN 200 Spring 2018 Prof. Dola Saha 1 Simple Program 2 Comments // Fig. 2.1: fig02_01.c // A first program in C begin with //, indicating that these two lines
More informationCIS133J. Working with Numbers in Java
CIS133J Working with Numbers in Java Contents: Using variables with integral numbers Using variables with floating point numbers How to declare integral variables How to declare floating point variables
More information