Introduction to Programming Lecture 25

Introduction to C++ language

In Coming Lectures C++ Features Classes Object

Today’s Lecture Default Function Arguments Inline Functions Classes

Rules for Structured Programming Do Modular programming Write small function Every function should perform a specific well defined task Function should obey single entry single exit rule

Liberally Comment the code

Object Oriented Language

Early 1980's Bjarne Stroustrup at Bell Labs

C with Classes C++ Java

Default Function Arguments

power ( x , n ) ;

void f ( int i , double x ) ;

void f ( int i =1 , double x = 10.5 ) { -- }

Example 1 void f ( int i = 1 , double x = 10.5 ) { cout<<“i = ”<<i; cout<<“ x = “<< x<<endl; }

Example 1 main ( ) { f ( ) ; f ( 2 ) ; f ( 2 , 12 ) ; } Output i = 1 x = 10.5 i = 2 x = 10.5 i = 2 x = 12

void f ( double x=10.5 , int i ) ;

The declaration of variables inside the code

while ( condition ) { // body of the while loop }

{ int i ; --- }

Scope of Variable When you declare a variable inside the block then the variable exists in that block.

Example 2 for ( int i = 0 ; i < 3 ; i++ ) { int temp = 22 ; cout << "\n i = " << i << "temp = " << temp ; } cout << "i = " << i ;

Inline functions

inline

Example 2 #define SQUARE ( X ) X * X main ( ) { int i = 5 , j = 10 , k ; : k = } i + j * i + j ; SQUARE ( i + j ) ;

Example 3 #define SQUARE ( X ) ( X ) * ( X ) main ( ) { int i = 5 , j = 10 , k ; k = } SQUARE ( i + j ) ; ( i + j ) * ( i + j ) ;

Example 3 #define MAX ( A , B ) ( ( A ) > ( B ) ? ( A ) : ( B ) ) inline f ( int a, int b ) { if ( a > b ) return a ; return b ; } void main ( ) int i , x , y ; x = 23 ; y = 45 ; i = MAX ( x++ , y++ ) ; // Side - effect : larger value incremented twice cout << "x = " << x << " y = " << y << '\n' ; i = f ( x++ , y++ ) ; // Works as expected

Function Overloading

Operator Overloading

Overloading Using the same name to perform multiple tasks or different task depending on the situation

double Intsquareroot ( int i ) ; double Doublesquareroot ( double x ) ;

Example 4 int squareroot ( int i ) { // body of the function } double squareroot ( double x )

Example 4 main ( ) { double i , x ; int j = 5 , k ; i = squareroot ( 10.5 ) ; cout << i << endl ; k = squareroot ( j ) ; cout << k << endl ; }

Example F ( int a , int b ) ; F ( int a , int b , int c ) ; main ( ) { ----------- F ( 1 , 2 ) ; // F ( int a , int b ) ; is called F ( 1 , 2 , 3 ) ; // F ( int a , int b , int c ) ; is called }

int f ( int a ) ; double f ( int a ) ;

Name Mangling