CSCE 110 PROGRAMMING FUNDAMENTALS

Transcription

1 CSCE 110 PROGRAMMING FUNDAMENTALS WITH C++ Prof. Amr Goneid AUC Part 2. Overview of C++ Prof. Amr Goneid, AUC 1

2 Overview of C++ Prof. Amr Goneid, AUC 2

3 Overview of C++ Historical C++ Basics Some Library Functions Expressions & Assignment Simple Input/Output Prof. Amr Goneid, AUC 3

4 Historical 1967: BCP language (Martin Richards, Cambridge) 1969: B language (Ken Thompson, Bell labs) Early 1970 s: C language & Unix Operating System (Dennis Ritchie, Bell Labs) Prof. Amr Goneid, AUC 4

5 Historical Mid-1980 s: Early C++ derived from C (Bjarne Stroustrup, Bell labs) 1998: Formally standardized C++, an OOP language Prof. Amr Goneid, AUC 5

6 1. C++ Basics Example Program Style, Declarations Data Types Constants Declaring Constants & variables Prof. Amr Goneid, AUC 6

7 1.1 Example Program: Sorting an Array of Integers Prof. Amr Goneid, AUC 7

8 Sorting an Array of Integers # include <iostream> using namespace std; // Functions Used void selectsort (int a[ ], int n); // Function Prototype int main() { const int MAX = 100; int a[max], k, n; // Start of main function // Data Declarations Prof. Amr Goneid, AUC 8

9 Example Program: Main Function Actions /* Begin Main Actions */ cin >> n; // Read size of data if (n > MAX) n = MAX; // to prevent array overflow for (k = 0; k < n; k++) cin >> a[k]; // Read data into array selectsort(a,n); // Call sorting module for (k = 0; k < n; k++) cout << a[k]; // Write sorted data cout << \n // Move to a new line return 0; // No errors } /* End. Main Function */ Prof. Amr Goneid, AUC 9

10 Example Program: Sorting Module (Function) void selectsort (int a[ ], int n) { // Begin Module int i, j, min, temp; // Module Local Data for (i = 0; i < n-1; i++ ) // Begin module action { min = i; for ( j = i+1; j < n; j++) if (a[j] < a[min] ) min = j; temp = a[min]; a[min] = a[i]; a[i] = temp; } } // End Module Prof. Amr Goneid, AUC 10

11 1.2 Style Lines Separators (spaces, lines, comments) Comments ( //.. Single line or /*..*/ ) Case sensitive ( e.g. MAX, max) Keywords ( e.g. for if return..) use lowercase letters User Identifiers (e.g. MAX, min, a, n, selectsort,.. etc) Prof. Amr Goneid, AUC 11

12 Style (continued) Constants (e.g. MAX,100, \n etc) Operators (e.g. <= ++ + >> etc) Punctuators (e.g. ( ) ; { } etc) Keywords, identifiers, constants, operators and punctuators are called TOKENS Compiler Directives Prof. Amr Goneid, AUC 12

13 Compiler Directives #include Compiler directive Processed at compilation time Instructs compiler on what you want in the program #include <iostream> Adds library files to program Used with < > Also user defined Prof. Amr Goneid, AUC 13

14 Some Declaration Keywords Modules (Functions): main() void <function name>(..) Data Declaration: const for constant data int, float, etc, for data types string for user defined strings Prof. Amr Goneid, AUC 14

15 1.3 A Classification of Data Types Data Type Scalar Data Structure Integer Floating Character Logical (bool) Pointer Arrays Structs Unions Classes Files Streams strings.. Prof. Amr Goneid, AUC 15

16 Some Scalar Data Types Integers: int short unsigned int long Floating: float double long double Character: char unsigned char Logical (Boolean): bool Prof. Amr Goneid, AUC 16

17 Ranges of Scalar Data Types int, short 2 bytes -32, ,767 unsigned int, unsigned short 2 bytes ,535 long 4 bytes -2G.. 2G unsigned long 4 bytes 0.. 4G float 4 bytes ~ E +/- 38 (7 digits) double 8 bytes ~ E +/- 308 (15 digits) long double 10 bytes ~ E +/ (19 digits) Prof. Amr Goneid, AUC 17

18 Ranges of Scalar Data Types char 1 byte unsigned char 1 byte bool 1 byte true / false non-zero / zero Note: Integer, character and boolean types are called Ordinal Types because their members can be listed by rank. Prof. Amr Goneid, AUC 18

19 1.4 Examples of Constants Predefined: true false SHRT_MAX (32767) Integer: 79 (decimal of type int) L (decimal of type long) Floating: e E+5 (decimal of type double) Character: A \n (type char) String Literals: Hello (class string) Prof. Amr Goneid, AUC 19

20 1.5 Declaring & Initializing Constants Syntax : const <type> <name> = <value>; Examples: const int MAX = 100; {integer} const bool says = true; {Boolean} const string message = warning! ; {String literal} const float KmperMile= F; {float} const alpha = E-15; {double} const Large = L; {long} const char Initial = H ; {char} Prof. Amr Goneid, AUC 20

21 Declaring & Initializing Variables Syntax: <type> <name>, <name>.. ; or <type> <name> = <value>; Examples: unsigned char pixel ; int k = 2197; float x, y ; char c ; bool test ; string name = Ann W. Wolf ; Prof. Amr Goneid, AUC 21

22 Assigning Constants to Variables changes initial values Examples: pixel = 212; k = ; x = ; c = H ; test = false; name = John W. Wolf ; k = SHRT_MAX; Prof. Amr Goneid, AUC 22

23 2. Some Library Functions Prof. Amr Goneid, AUC 23

24 Some Library Functions To invoke: FunctionName (x) returns value of function for argument x Examples: char(65) returns A int( A ) returns 65 sqrt(4) returns 2.0 abs(-6) returns 6 sin(1.5708) returns 1.00 Prof. Amr Goneid, AUC 24

25 Library Functions(continued) cos(0.0) returns 1.0 atan(1.0) returns pi/4 tan(0.0) returns 0.0 log(2.0) returns exp(2.0) returns pow(4,1.5) returns 8.00 = ceil(2.67) returns 3.0 floor(2.67) returns 2.0 Random(n) returns random int 0.. n-1 Prof. Amr Goneid, AUC 25

26 Using a Library Function //Computes w = (1+z) 2.6 z 1.45 / (1-z) 3.2 # include <cmath> // pow function # include <iostream> // I/O functions using namespace std; int main ( ) { float w, z ; cout << Enter z: ; cin >> z ; w = pow(1+z,2.6) * pow(z,1.45) / pow(1-z,3.2); cout << Value of w = << w << endl; return 0 ; } Prof. Amr Goneid, AUC 26

27 3. Expressions & Assignment Syntax Arithmetic Expressions Logical Expressions Relational Expressions Assignment Statement Overall Operator Precedence More on Arithmetic and Assignment Prof. Amr Goneid, AUC 27

28 3.1 Syntax Form1 Form2 U-Op operand operand B-Op operand e.g -5!found a + b x > y + 32 (c >= 65) && (c <=90) Prof. Amr Goneid, AUC 28

29 Syntax Operands: Constants e.g. 5 false Variables e.g. x a[3] Functions e.g. sqrt(7) sin(y) Expression e.g. x + y a > b Operators: Arithmetic Logical Relational Assignment Compound Prof. Amr Goneid, AUC 29

30 3.2 Arithmetic Expressions Operators: Unary Minus and Plus (-) (+) Multiplication, Division, Modulus ( * / % ) Addition, Subtraction ( + - ) Examples: -5 a*b sqrt(5)/2.0 x % m y - b (a+sqrt(y))/(6- sin(pi*y)) m / n - k Prof. Amr Goneid, AUC 30

31 Arithmetic Expressions Examples: 5 / 2 is 2 (int operands, int value) 5.0 / 2.0 (float operands, float value) 5.0 / 2 (Mixed operands, float value) 7 % 2 is 1 3 % 5 is 3 (% for int only) /3 + 5 is 9 but (2 + 6) / (3 + 5) is 1 Prof. Amr Goneid, AUC 31

32 Arithmetic Expressions Operator Precedence: ( ) Highest unary + - * / % Add (+), Subtract (-) Lowest Prof. Amr Goneid, AUC 32

33 Example How many Hours, Minutes, Seconds are in n seconds? int n, hrs, mins, secs, rem; hrs = n / 3600; rem = n % 3600; mins = rem / 60; secs = rem % 60; Prof. Amr Goneid, AUC 33

34 3.3 Logical Expressions Operators:! (unary not) (or) && (and) Operands of Boolean type Result: Boolean ( true, false ) Examples:! true is false a b! (x<y) c && d Prof. Amr Goneid, AUC 34

35 Truth Table for Logical Operators 0 false, 1 true x y!x x y x && y Prof. Amr Goneid, AUC 35

36 3.4 Relational Expressions Operators: == < > <= >=!= Result: Boolean Examples: a > b c <= 6 sqrt(x) >= y z!= w a+b == c+d A < a name1!= name2 Prof. Amr Goneid, AUC 36

37 3.5 Assignment Statement The Assignment operator ( = ) Syntax: variable = expression; Examples: int x, y ; bool a,b,c ; x = 3; y = 2*x; a = true; a = x > y; c = a b; Prof. Amr Goneid, AUC 37

38 3.6 Overall Operator Precedence Parentheses ( ) Highest Unary:! + - Multiplicative: * / % Additive: + - Relational: < > <= >= Relational: ==!= Logical: && Logical: Assignment = Lowest Example: d =!(x+y < z) && (2*b == c); Prof. Amr Goneid, AUC 38

39 3.7 More on Arithmetic and Assignment Increment and Decrement Operators: ++operand --operand (increment/decrement operand then evaluate expression) operand++ operand-- (evaluate expression then increment/decrement operand ) e.g. n++, ++n is shorthand for n = n + 1 Prof. Amr Goneid, AUC 39

40 Increment and Decrement Operators Examples: int a = 3; int b = 5; int c; c = a + b++; yields a == 3, b == 6, c == 8 c = a + ++b; yields a == 3, b == 6, c == 9 c = a + b--; yields a == 3, b == 4, c == 8 c = a + --b; yields a == 3, b == 4, c == 7 Prof. Amr Goneid, AUC 40

41 Multiple & Compound Assignment Multiple Assignment: c = a = b; d = (a = b + 3) / c; Compound Assignment: (Reassign after doing operation) e.g. a = a + b; //var = var op expr; can be written: a += b; //var compound-op expr; compound operators += -= *= /= %= e.g. c /= (x + 2); is c = c / (x + 2); Prof. Amr Goneid, AUC 41

42 4. Simple Input/Output Prof. Amr Goneid, AUC 42

43 Simple Input/Output Standard I/O Devices: cin standard input stream (keyboard) cout standard output stream (screen) Defined in #include <iostream> Extraction Operator: >> DataVariable extracts one data item from cin to a variable Insertion Operator: << DataElement inserts one data element in cout Prof. Amr Goneid, AUC 43

44 Simple Input/Output Keyboard Input: cin >> v ; cin >> v1 >> v2 ; Variables are entered with spaces between them. ENTER or RETURN end input. e.g. int a,b; float x; string name; cin >> name; cin >> a >> b >> x; A.W.Wolf Prof. Amr Goneid, AUC 44

45 Data Types and cin Don t mix types with cin int x; cin >> x; If Keyboard input is 16.6 The value placed in x would be 16 Prof. Amr Goneid, AUC 45

46 Other Characteristics of cin Leading blanks ignored (floats, int, char, bool and strings) Char read 1 at a time (1 non blank) Case issues int or float will read until space Stings same as int and float Prof. Amr Goneid, AUC 46

47 Simple Input/Output Screen Output: cout << d; cout << d1 << d2..; Examples: int a,b,c; float z; cout << Enter a,b,c: ; Enter a,b,c: cin >> a >> b >> c; cout << a << 2*b << endl; 6004 z = sqrt(a + b * c); cout << Result is ; cout << z; Result is Prof. Amr Goneid, AUC 47

48 Example Program : Hello.cpp // FILE: Hello.cpp // DISPLAYS A USER'S NAME #include <iostream> #include <string> using namespace std; int main () { Prof. Amr Goneid, AUC 48

49 Hello.cpp char letter1, letter2; string lastname; } // Enter letters and print message. cout << "Enter 2 initials and last name: "; cin >> letter1 >> letter2 >> lastname; cout << "Hello " << letter1 << ". " << letter2 << ". " << lastname << "! "; cout << "We hope you enjoy studying C++." << endl; return 0; Prof. Amr Goneid, AUC 49

50 Hello.cpp Program Input/output Enter 2 initials and last name: SAWolf Hello S. A. Wolf! We hope you enjoy studying C++. Prof. Amr Goneid, AUC 50