learning c++ - introduction to c++ programming 1

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Introduction To C++ ProgrammingAli Aminian & Bardia Nezamzadeh

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Section Outline

• Workspace• Basics of C++ Environment• Definition of Types• Operations in C++

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Section Outline


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Workspace

• One of the most famous workspaces is “Microsoft Visual Studio”

• Creating a project :lets follow these pictures :

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Workspace(cont.)

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Section Outline


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• Comments-Single-line comment

• Begin with : // this is comment (Fortran : !)

-Multiple-line comment• Begin with : /* … /* this is a multiple line • End with : …*/ comment. We still have

this line!*/

• Preprocessor directives-Processed by preprocessor before compiling-Begin with # include <math>

Basics of C++ Environment

Adding math library to the project.

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• Different type of files in C++– Header files (.h)– cpp files (.cpp)– Most important headers:

iostream.h iomanip.h math.h cstdlib.h

Basics of C++ Environment(cont.)

Standard input/output

Manipulate stream format

Math library function

Conversion function fortext to number , number to text, memory allocation, random numbers and various other utility functions

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• Program Frameworkint main() { ………………..………………..……………….. return 0;

}

(Frotran Framework:)PROGRAM name………………..………………..……………….. END

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• Some important Syntaxes– include<>– main()– cin>> , cout<<

• These are like READ , PRINT– ; (Semicolon)

• Shows the end of line . (works the same as in Fortran)


In next slides we introduce the other syntax symbols, these are most familiar for any program which we could see in any code

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Basics of C++ Environment(cont.)Phases of C++ Programs:

1. Edit2. Preprocess3. Compile4. Link5. Load6. Execute Loader

PrimaryMemory

Program is created inthe editor and storedon disk.

Preprocessor programprocesses the code.

Loader puts programin memory.

CPU takes eachinstruction andexecutes it, possiblystoring new datavalues as the programexecutes.

CompilerCompiler createsobject code and storesit on disk.

Linker links the objectcode with the libraries,creates a.out andstores it on disk

Editor

Preprocessor

Linker

CPU

PrimaryMemory

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Disk

Disk

Disk

Disk

Disk

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Basics of C++ Environment(cont.)1 // Printing multiple lines with a single statement2 #include <iostream>3 4 // function main begins program execution5 int main()6 {7 std::cout << "Welcome to C++!\n";8 9 return 0; // indicate that program ended successfully10 11 } // end function main

Comments

Preprocessor directive to include input/output stream header file <iostream>We include this library to use the std::cout command for printing.

Function main appears exactly once in every C++ program..

Special CharactersWe use these characters to write some characters that can not be written in normal way:\n Enter\t Tab\\ backslash itself!

Keyword return is one of several means to exit function; value 0 indicates program terminated successfully.

Welcome to C++!

Output:

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Section Outline

• Workspace • Basics of C++ Environment• Definition of Types• Operations in C++

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Definition of Types

• Floating point variables– float : 6 digits after floating point– double : 12 digits after floating point (more

precision)All of above types are useful to store real values such as: 0.12E5 Or 2.3212

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Definition of Types(cont.)

• Integer variablesWe can use following words to do some alternative with int type:– short – unsigned int– unsigned short – long– int – unsigned longThese words change range and starting point of

integer variables :e.g. short int a; //range -32768 to 32767

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Type Min. range Max. range

short -32768 32767

unsigned short 0 65535

int -2147483648 2147483647

unsigned int 0 4294967295

long -9223372036854775808 9223372036854775807

unsigned long 0 18446744073709551615


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• bool– This type has just two values: (true, false)– Note : in Fortran we use LOGICAL and .true. And .false.

combination Instead.• char

– This type is used to store ASCII characters– e.g. char a =‘Q’;

• enum– It creates a list, in witch every elements has a numberand we can use the elements instead of numbers(notice to example in next slide)

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E.G. :If we define such an enum :

enum Day{SAT,SUN,MON,TUE,WED,THU,FRI}

Now if we define a variable from Day type then this variable can accept the values that defineInside the Day type such as SAT, SUN, MON,…

e.g. Day mybirthday = MON;

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NOTES:variable precision:

1.2 / 2 returns integer or double?Casting:

e.g. : a = (int) c; //a is int and c is double (c was 12.63)

If we didn’t use cast in this example, C++ would store 12 inside a.

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• We can have our own types with typedef keyword.e.g. typedef long double real;

real a; //a is a long double variable now

Exactly the same type in C++ Type in Fortran

short INTEGER *2

int INTEGER *4

long int INTEGER *8

float REAL*4

double REAL*8

long double REAL*16

char CHARACTER

bool LOGICAL

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• MORE NOTES! we use const command to define constant

variables ( Fortran : PARAMETER )e.g. const int a = 12;

there is no need to write & when we want to write multiple line commands

C++ is a case sensitive language ( vs. Fortran )

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Section Outline

• Workspace • Basics of C++ Environment• Definition of Types• Operations in C++

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Operations in C++

• Conditional operands

other operands : < , <= , => , >

Fortran C++.AND. && And

.OR. || Or

.NEQV. =! Not equivalent

.EQV. == Equivalent

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Operations in C++

• If (condition) {statement }• If , else

if (a==true){b=b+1;}

else

{b=b-1;}

It is important that how compiler , compile these operations

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Operations in C++

• for(init;condition;command) {statement}

for(i=0; i<10; i++){

b--; // b=b-1}

variable i will advance from 0 itself to 9 itself during the loop

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Operations in C++

• while(condition) {statement}while(a)//if a is true{

b++; // b=b+1if(b==100){

break;}

} notes :

break: breaks the loop and steps outCtrl+C: manually breaking the loop!

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Operations in C++(cont.)

• Variable++ / ++Variablex=y++ is different from x=++y

• > , < , => , != , == (Comparisons operand) , =• ||, && (Logical operand)• condition ? expression1 : expression2

– if(condition) {expression1 } else {expression2}• goto : label

you must know what want to do exactly otherwise this is very dangerous !

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In future :

i. Pointers and related arguesii. Functionsiii. Class and related conceptsiv. ERRORS

learning c++ - introduction to c++ programming 1

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