Lecture 5: Computer Languages. Programming Environments (IDE) COS120 Software Development Using C++ AUBG, COS dept

2 Lecture Contents: t Programming Environments. Integrated Development Environments (IDE) t Microsoft Visual Studio: C++ IDE t Introduction to project concept –Solution and project(s) t Sample programs in C++

3 Previous lecture reminder Title: A Tutorial Introduction to C++ Source: Friedman/Koffman, Chapter 02 Have a quick look at next approx 40 slides to refresh your knowledge on previous lecture

Overview of C++ Chapter 2

5 2.1 C++ Language Elements t Comments make a program easier to understand t // Used to signify a comment on a single line t /* Text text */ use if comments on multi lines t Don’t embed comments within /* */ comments

6 Compiler Directives t #include –Compiler directive –Processed at compilation time –Instructs compiler on what you want in the program t #include –Adds library files to program –Used with –Also “ “ user defined

7 Compiler Directives t Stream data type –Object that is a stream of characters –Defined in iostream –Entered on the keyboard( cin ) –Displayed on monitor( cout )

8 Declarations t Based on data needs (data identifiers) t Each identifier needed must be declared t Comma used to separate identifiers  cin and cout are standard, undeclared identifiers –Special elements called streams –cin - input stream –cout - output stream –Included with the iostream, not declared

9 Executable Statements  cout get output cout << " \nEnter the fabric size in square meters: " ;  cin get input cin >> sizeInSqmeters; t Assignment sizeInSqyards = metersToYards * sizeInSqmeters;

Reserved Words and Identifiers t Reserved words have special meanings –Can NOT be used for other purposes ( const, float and void are some examples) t Identifiers (variables) –Used to store data by the program (user defined) –Valid identifiers - letter, letter1, _letter –Invalid identifiers - 1letter, const, hell o

11 Reserved Words and Identifiers t Special symbols –C++ has rules for special symbols – = * ; { } ( ) // >

12 Upper and Lower Case t C++ - case sensitive language –Compiler differentiates upper & lower case –Identifiers can be either –Be careful though ( cost != Cost ) t Blank spaces –Use space to make program readable –Use care in placing spaces

Data Types and Declarations t Predefined data types –int (integer numbers) Positive or negative whole numbers INT_MAX - largest int allowed by compiler –float or double (real numbers) Positive or negative decimal numbers

14 Data Types and Declarations t Predefined data types –bool (Boolean) true false –char (Characters) Represent single characters

15 Data Types and Declarations  The basic integer type is int –The size of an int depends on the machine and the compiler On PC’s it is normally 16 or 32 bits t Other integers types –short : typically uses less bits –long : typically uses more bits

16 Data Types and Declarations t Floating-point types represent real numbers –Integer part –Fractional part  The number breaks down into the following parts –108 - integer part – fractional part

17 Data Types and Declarations t C++ provides three floating-point types: –float –double –long double

18 Data Types and Declarations t Predefined data types –char (characters) Individual character value (letter or number) Character literal enclosed in single quotes ‘A’ –bool (true / false) t Ordinal types –intboolchar –Values can be listed

19 Data Types and Declarations  Character type char is related to the integer types t Characters are encoded using a scheme where an integer represents a particular character

20 Data Types and Declarations t ASCII is the dominant encoding scheme –Examples ' ' encoded as 32 '+' encoded as 43 'A' encoded as 65 'Z' encoded as 90 'a' encoded as 97 'z' encoded as 122

21 string Class t String object data type –A literal string constant is a sequence of zero or more characters enclosed in double quotes – "Are you aware?\n" –Individual characters of string are stored in consecutive memory locations –The null character ( '\0' ) is appended to strings so that the compiler knows where in memory string ends

22 string Class t String literal –"A" –"1234" –"Enter the distance:" t Additional data types included in library #include –Various operations on strings

23 Declarations t Identifiers should be –Short enough to be reasonable to type (single word is norm) Standard abbreviations are fine (but only standard abbreviations) –Long enough to be understandable When using multiple word identifiers capitalize the first letter of each word

24 Declarations t Examples –char response; –int minelement; –float score; –float temperature; –int i; –int n; –char c; –float x;

25 Constant Declarations t Types of named constants: –integer –float –char –bool –string objects t Associate meaningful terms –const float PAYRATE = 10.25;

26 Hello.cpp –full text of program // FILE: Hello.cpp // DISPLAYS A USER'S NAME #include using namespace std; int main() { 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; }

27 Hello.cpp Program output Enter first 2 initials and last name and press return: EBKoffman Hello E. B. Koffman! We hope you enjoy studying C++.

Executable Statements t Memory status –Before and after t Assignments –Form: result = expression; –sizeInSqyards = metersToYards * sizeInSqMeters; –sum = sum + item;

29 Arithmetic Operators t +Addition t - Subtraction t *Multiplication t /Division t % Modulus

30 Input / Output Operations t Input –#include library –cin >> sizeInSqmeters; t Extracted from cin (input stream)  >> Directs input to variable  cin associated with keyboard input (stdin) t Used with int, float, char, bool and strings

31 Data Types and cin t Don’t mix types with cin int x; cin >> x; Keyboard input 16.6 Value placed in x would be 16

32 Other Characteristics of cin t Leading blanks ignored (floats, int, char, bool and strings) t Char read 1 at a time (1 non blank) t Case issues  int or float will read until space  Strings same as int and float

33 General Form for cin Form: cin >> dataVariable; cin >> age >> firstInitial;

34 Program Output  Output stream cout  << Output operator (insertion operator) –cout << “my height in inches is: “ << height; t Blank lines – endl or “\n” or ‘\n’ Form:cout << dataVariable;

General Form of a C++ Program t General program form –Function basic unit (collection of related statements) –A C++ program must contain a main function void main() {... } –int - function returns integer value –void - function does not return value –main - lower case with () –{ } - Braces define the function body

36 General Form of a C++ Program t General form of function body parts –Declaration statements Variables and constants –Executable statements C++ statements

37 General Form of a C++ Program t General form // File: filename // Program description: #include directives int main() { Declarations section Executable statements section }

38 General Form // Name: Mike Hudock // Date: March 10, 2012 // Files: file1.cpp // Changes : // Program description:

39 General Form t Use comments throughout code to highlight points of interest t Strange identifiers t Function explanations t Algorithm definitions

Arithmetic Expressions  int data type –+ - * /, Assignment, input and output on int –% Only used with int t Examples of integer division 15 / 3 = 5 15 / 2 = 7 0 / 15 = 0 15 / 0 undefined

41 Modulus and Integer t Used only with integer and yields remainder t Examples of integer modulus 7 % 2 = % 100 = % 5 = 4 15 % 0 undefined

42 Mixed-type Assignments t Expression evaluated t Result stored in the variable on the left side t C++ can mix types float a, b, x; int m, n; a = 10; b = 5; x = m / n;

43 Expressions With Multiple Operators t Operator precedence tells how to evaluate expressions t Standard precedence order –() Evaluated first, if nested innermost done first –* / % Evaluated second. If there are several, then evaluate from left-to-right –+ - Evaluate third. If there are several, then evaluate from left-to-right

44 Mathematical Formulas in C++

Common Programming Errors t Syntax –Programs rarely compile –Something always goes wrong –Systematic solutions t Compiler not descriptive –Look at line number before and after error –Watch missing ; and }

46 Common Programming Errors t Run-time errors –Illegal operation (divide by 0) t Logic errors –Program functions differently than you expect

47 IDE MS Visual Studio

48 Introduction to MS Visual C t When you activate IDE for the first time, it’s time for you to make your choice: t General development settings t Or t C++ development settings t Or t …

49 Intro to MS Visual C++ Creating Unmanaged Application To build a console application that will run without.NET framework, follow these steps: 1. Open Visual Studio. 2. On the Start Page, click New Project…. If the Start Page isn’t visible, Choose File, New, Project. 3. Select the Visual C++\Win32 from Installed Project Templates on the left and select Win32 Console Application Project type on the right. 4. Enter project name, for example ConsoleApplication1, project location, for example Q: drive and click OK. 5. Click Finish from the wizard that appears. The wizard generates the skeleton of an unmanaged C++ application. To build the project, follow these steps: 1. Choose Build, Build Solution or press F7 To run the project, follow these steps: 1. Choose Debug, Start Without Debugging or press Ctrl+F5

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57 Exercise 5.1 Build and run a program: To compute and display the volume of a pool.

58 Exercise 5.4 Build and run a program: To convert Celsius degrees to Fahrenheit degrees Fahr = 9./5.*Cel+32

59 Exercise 5.5 Build and run a program: To convert Fahrenheit degrees to Celsius degrees Cel = 5./9.*(Fahr-32)

60 Exercise 5.3 Build and run a program: To add, subtract, multiply and divide two numeric values.

61 Exercise 5.2 Build and run a program: To convert feet and inches to meters.

62 Before lecture end Lecture: Computer Languages. Programming environments (IDE) More to read: Friedman/Koffman, Chapter 02

63 Thank You For Your Attention!