CSci 160 Computing Science I. Sarah Carruthers Fall 2017

Transcription

1 CSci 160 Computing Science I Sarah Carruthers Fall 2017

2 Administrivia Lecture: Tues. & Thurs. 11:30-1:00, Tues. 4:00-5:00 Instructor: Sarah Carruthers Office Hours: Mon. 3-4PM, Tues. 10:30-11:30 AM Course homepage: D2L Syllabus available on D2L, and handout Text:

3 Administrivia Mark breakdown: Assignments: 15% Reading Assessments: 10% Labs: 20% Exams: 55% (must pass final to pass the course) To pass the course you must pass both the lab portion of the course and the final exam

4 Course Topics Overview of software, hardware, and the development cycle C++ Basic data types Input and output Functions in C++ Control structures: branching and loops Abstract Data Types (arrays, structs, pointers) Algorithms Modularity and Design Dynamic data structures (linked lists)

5 Course Learning Outcomes Program Comprehension: Analyze and explain the behaviour of simple programs using the fundamental programming constructs Variables Expressions Assignments I/O Control constructs Functions Parameter Passing Recursion

6 Course Learning Outcomes Program Design: Design, implement, test, and debug a program that uses each of the following programming constructs: Basic computation simple I/O Standard conditional structures Standard iterative structures definitions of functions parameter passing constants enumerated types

7 Course Learning Outcomes Primitive Data Types: Identify and describe the use of primitive data types Write programs that use primitive data types Recursion: Describe the concept of recursion, and give examples of its use Identify the base case and the general case of a recursively-defined problem

8 Course Learning Outcomes Conditional and Iterative Constructs: Choose appropriate conditional and iteration construct for a given programming task Modify and expand short programs that use standard conditional and iterative control structures and functions

9 Course Learning Outcomes Advanced Data Types Write programs that use each of the following data structures: Arrays Structs Strings Write programs that use pointers for dynamic memory allocation and release Describe the concept of dynamic data structures and their uses Describe the concept of wild and dangling pointers Recognize the risks of wild an dangling pointers

10 Course Learning Outcomes Code Quality Apply consistent documentation and program style standards Describe the importance of consistent documentation and program style standards Create readable and maintainable software using conventions like documentation and program style standards

11 VIU Graduate Attributes Three Pillars: Literacies Intellectual and Practical Skills Civic Engagement

12 VIU Graduate Attributes Three Pillars: Literacies Technological Literacies Information Literacies Scientific Literacies Intellectual and Practical Skills Civic Engagement

13 VIU Graduate Attributes Three Pillars: Literacies Intellectual and Practical Skills Disciplinary Expertise Critical Thinking Inquiry and Ways of Knowing Safe and Ethical Practices Active Learning Civic Engagement

14 VIU Graduate Attributes Three Pillars: Literacies Intellectual and Practical Skills Civic Engagement Capacity to Engage in Respectful Relationships Foundations for Lifelong Learning Ethical Reasoning

15 Labs Weekly hands-on exercises 10 labs, each due before your next lab Each lab will consist of: in-lab portion (practice, help, not for marks) take home portion (for marks) self-assessment (for marks)

16 Assignments one middle of term (Oct. 29) one at end of term (Dec. 5) individual work to showcase what you ve learned

17 Assignments For 2 assignments: I will give you a set of requirements it is your job to design a solution it is OK to discuss your idea with your classmates, but you should each come up with your own design (they may be similar) it is your job to turn your design into code it is NOT OK to share your code it is OK to help debug your classmate s code

18 Reading Assessments Each week pre-readings will be posted You are responsible for these readings Assessed by online quiz

19 Lectures Lectures will consist of: syntax of C++ example code in-class exercises/quizzes quick response using Socrative or download the app hand-written coding exercises

20 Bonus Marks Everyone is eligible for up to 3% bonus marks, for completing up to 3 of the following: Video tutorial Blog tutorial Posting helpful material Finding an error in labs, assignments, demo code Getting help when you re stuck Helping a classmate when they re stuck Completing all the lab bonuses All except lab bonuses must be posted to D2L Discussion board Submit bonus checklist to D2L Details are on D2L

21 How to succeed in CSCI160 Attend labs and lectures In lecture we will cover: specifics of the language practice problems example code In lab you will get to: make mistakes in a safe environment ask for help practice

22 How to succeed in CSCI160 Practice practice practice! you re learning many things at once: how to program how to think like a computer scientist how to work on the command line a new language Do your own work the labs are there for you to practice cheating will not be tolerated

23 How to succeed in CSCI160 Practice practice practice! try the examples we do in class try to code things on your own when studying, redo your labs make code flash cards one side a verbal description other side the code

24 How to succeed in CSCI160 Write code by hand you ll need to write code for exams, don t wait until the midterm to practice Read code help your classmates when they re having trouble read their code and help find bugs

25 How to succeed in CSCI160 Plagiarism and cheating: Don t do it! Labs and assignments are designed to challenge you so that you can learn. Cheating bypasses this No learning = no passing exam (and you must pass the final to pass the course)

26 How to succeed in CSCI160 If you get stuck Come talk to me office hours after class by ask tutors for help talk to your classmates

27 Cheating copying from another person allowing someone to copy from you claiming someone else s work as yours collaborating on a test without authority taking a test for someone else acquiring academic material belonging to faculty or staff and more...

28 Plagiarism submitting another person s words as your own submitting another person s idea, opinion, or theory as your own even if paraphrased submitting facts, statistics, or illustrative materials without appropriate citation regardless of source

29 Plagiarism submitting another person s words as your own submitting another person s idea, opinion, or theory as your own even if paraphrased submitting facts, statistics, or illustrative materials without appropriate citation regardless of source

30 Penalty for Plagiarism and Cheating May include: failure of assignment or exam failing grade in course suspension from program

31 How to not cheat Write your own code Don t let others copy your code log out when you leave the room don t leave usb drives unattended don t throw out paper copies of work

32 The grey area.. Labs: in lab we will discuss algorithms and design strategies these are shared by everyone, and it is your job to implement them please talk to each other about these algorithms and ideas please do not copy code from each other look, think, write

33 Building Knowledge

34 Grammar Computational Thinking Creating Programs

35 Abstract Data Types Modularization Grammar Computational Thinking Creating Programs

36 Advanced ADTs Writing Programs Abstract Data Types Modularization Grammar Computational Thinking Creating Programs

37 How this course works We start with building blocks of the language (ABCs) Learn how to put these blocks together correctly (syntax) The green habit is crisply meandering. Learn how to put these blocks together meaningfully (semantics) There is a large rabbit on the hill who eats lots of carrots. Learn how to take a problem and craft a solution (write an essay) Tell a story that someone else understands, that is interesting to them

38 Today Quick look at history of C++ and programming Writing, compiling, and executing code Software and algorithms Programming Languages

39 C++ Programming Language a general-purpose, statically typed, free-form, multi-paradigm programming language

40 C++ Programming Language History Based on C language, it is C with Classes

41 Why learn C++? It is commonly used It is closely related to many other popular languages Java C PHP Perl It is versatile and multi-purpose

42 Basics of programming languages How we (as humans) talk to computers Different levels of language: low level languages that computers actually understand machine code assembly language hard for humans to read high-level languages that humans easily understand use English words (often) still need to be more rigorous and strict than natural language

43 How to talk to computers

44 Add 2 and 3 How to talk to computers int sum = 2+3; preprocess assemble link

45 A first C++ program /* * Author: Sarah Carruthers * Date: Fall 2017 * Purpose: A first program. Outputs "hello world" to the console, then terminates */ #include <iostream> int main(){ } std::cout << "Hello World" << std::endl; return 0;

46 How to compile In Linux, we use this command: g++ -Wall helloworld.cpp -o helloworldx If it works, we can then run our program on the command line:./helloworldx

47 Developing Software Programming requires Analyzing problem Determining an algorithm Expressing that algorithm in a programming language

48 Analyzing a problem What is the problem to be solved? User s perspective and needs Requirements should be carefully determined What general solution techniques are best? What data types/storage are best?

49 Developing an algorithm What is an algorithm? In small groups, think about this, and write down your definition...

50 Developing an algorithm What is an algorithm? In small groups, think about this, and write down your definition... Some answers:

51 Algorithm Definition: An Algorithm is a series of steps/instructions that solves a problem 1.Always outputs the correct result on any valid input 2.Always halts 3.Is unambiguous

52 Warm up Come up with an algorithm to draw a square:

53 Exercise Come up with an algorithm to draw the following Write it down as accurately as you can

54 Exercise Choose a partner, and swap algorithms Following their instructions exactly, draw what their algorithm describes did it work? If necessary, fix each other s algorithms

55 Exercise After thoughts: what were some common problems? how could you fix them?

56 Programming languages Which programming language is appropriate? Which are available/known? Which are supported by the user s system? Which are appropriate for the kind of problem being solved?

57 Programming languages High level Language Assembly Language Machine Language Human readable Mneumonics Binary sequences int i=3; MOV AL 3h

58 Programming languages High level Language Assembly Language Machine Language Human readable Mneumonics Binary sequences int i=3; MOV AL 3h

59 Programming languages Many, many languages to choose from, including: C, C++, Java, Objective-C, C#, Javascript, Python, Ruby... (general purpose) R, Fortran, Matlab, Mathematica... (scientific, mathematics) Prolog (logic) Cobol (business reporting)

60 This class: C++ Developed by Kernighan and Ritchie at Bell Labs Descendent of C Object-oriented Suitable for: cross platform development small projects large projects

61 How code becomes a program myprog.cpp #included header C++ preprocessor compiler assembler linker files temporary file myprog.s myprog.o myprog

62 Development Cycle We write programs to solve problems Understand the problem Break it down into manageable pieces Design a solution Think about the solution. Can it be improved? Write code (implement your solution) Test your solution Test incrementally AND Test final solution Fix as needed Follow a good development cycle a good system will work for small projects and large projects

63 Development Cycle Analyze the problem given Come up with a solution Code the solution Compile and run Test with data

64 Incremental Development Start small, compile, and add If planned properly it is possible to: Frame out the structure of the program Function declarations and definitions Leave body empty Add functionality a bit at a time

65 Analysis phase write a program to calculate the area of a circle Carefully describe the following: Inputs:? Outputs:? How do we turn inputs into outputs?

66 Analysis phase You need to write a program to calculate the area of a circle Analysis: Inputs: radius of the circle Outputs: area of the circle How do we turn inputs into outputs?

67 Design Phase High level breakdown of problem 1.Ask the user for the radius 2.Read in the radius from user 3.Calculate the area of a circle given the input radius 4.Output the area to the user

68 Design Phase Ask the user for the radius expect integer input Read the radius from user Calculate the area of a circle given the input radius Area = PI*radius*radius Output the area to the user

69 Exercise The problem: Convert a price in Euros to Canadian Dollars, then add 5% GST to it Do Analysis Phase Input, output, high level description Do Design Phase Detailed description

70 Analysis phase Convert a price in Euros to Canadian Dollars, then add 5% GST to it Carefully describe the following: Inputs:? Outputs:? How do we turn inputs into outputs?

71 Design Phase High level breakdown of problem 1...

72 Writing C++ Code Once we ve finished the Analysis and Design stages... Time to write some code! What is a programming language? What do we need to know to write in a new language like C++?

73 Programming Language Definition A programming language is a language designed to help you structure your instructions to a computer in a format that you can easily read and understand (relatively speaking). Programming is really just a way of organizing a task so that it is replicable by something else -- a computer. If you have ever given someone directions, or written down a recipe, you have some experience with programming.

74 Programming Languages: C++ C++ is a high-level language designed to be human readable still needs to be correct to work We care about 2 kinds of correctness syntax semantics

75 Syntax and Semantics Syntax (the grammar): What combinations of symbols are legally allowed English language example The panda eats, shoots and leaves. Sentence is well-formed Follows rules of English grammar Semantics (the meaning): What is the meaning of a syntactically correct phrase? English language example Colourless green ideas sleep furiously - Chomsky Syntactically correct, semantically meaningless or ambiguous

76 Exercise Come up with a sentence that is: 1.Syntactically correct and semantically incorrect 2.Syntactically incorrect

77 Syntax and Semantics: Why do we care? We have to follow the rules of syntax for our code to compile Code must be compiled in order to run If we want our code to do what we mean, we have to follow rules of semantics Semantically incorrect code will compile but might crash or do the wrong thing

78 Syntax and Semantics: Why do we care? Tools can help use catch syntax errors Compilers parse our code to make it into a program Analyze a string of symbols Based on formal grammar Syntax errors occur if incorrect Program will not compile and therefore not run

79 How code becomes a program myprog.cpp #included header C++ preprocessor compiler assembler linker files temporary file myprog.s myprog.o myprog

80 Compiler parses code into a tree-like structure Based on rules or syntax of the language If your code has syntax errors, compile fails

81 No program L myprog.cpp #included header C++ preprocessor compiler assembler linker files temporary file myprog.s myprog.o myprog

82 Survey

83 For Thursday get set up with Socrative or install the app (we will use it in class Thursday) Do the Intro. readings and the first reading assessment quiz (on D2L)