Functions

1 . FUNCTION OVERLOADING

2 . PASSING DEFAULT ARGUMENTS

3 . INLINE FUNCTION

Functions

Compiled By: Kamal Acharya

Function Overloading

When the function with the same name perform the multiple task it is called as the function overloading.

Example: If the function add() can add not only the integers but also the floats and strings it is overloaded.

The functions differ in one of the following things Number of parameters

Data types of parameters

Order of appearance


Number Of Arguments

#include<iostream.h>

#include<conio.h>

void print(char);

void print(char, int);

int main()

{

clrscr();

print('X');

print('Z',12);

getch();

return 0;

}

void print(char a)

{

cout<<"In the Single argument function"<<endl;

cout<<a<<endl;

}

void print(char a, int b)

{

int i;

cout<<"In the double argument function"<<endl;

for(i=0;i<b;i++)

{

cout<<a<<"\t";

}

}


Data Types of Parameters


#include<conio.h>

void add(int , int);

void add(float, float);

int main()

{

clrscr();

add(2,6);

add(12.6,1.2);

getch();

return 0;

}

void add(int a, int b)

{

cout<<"In the integer addition function"<<endl;

cout<<a+b<<endl;

}

void add(float a, float b)

{

cout<<"In the float addition function"<<endl;

cout<<a+b<<endl;

}


Oreder Of Appearance


#include<conio.h>

void fun(int , char);

void fun(char, int);

int main()

{

clrscr();

fun(2,'A');

fun('B',1);

getch();

return 0;

}

void fun(int a, char b)

{

cout<<"In the function with first argument integer and the second character"<<endl;

cout<<"The first argument is"<< a<<".The second argument is "<< b<<endl;

}

void fun(char a, int b)

{

cout<<"In the function with first argument character and the second integer"<<endl;

cout<<"The first argument is"<< a<<".The second argument is "<< b<<endl;

} Compiled By: Kamal Acharya

Passing Default Arguments

• Allows programmer to define a default behavior

A value for a parameter can be implicitly passed

Reduces need for similar functions that differ only in the number of parameters accepted


Default parameters must appear after any mandatory parameters

Bad example void Trouble(int x = 5, double z, double y) {

...

}

Cannot come before

mandatory parameters


Consider

void PrintChar(char c = '=', int n = 80)

{

for (int i = 0; i < n; ++i)

cout << c;

}

What happens in the following invocations?

PrintChar('*', 20);

PrintChar('-');

PrintChar();


Program to Illustrate Default Arguments


#include<conio.h>

void print(int a= 10 , char b='B');

int main()

{

clrscr();

print();

print(2);

print(1,'Z');

getch();

return 0;

}

void print(int a, char b)

{

int i;

for(i=0;i<a;i++)

{

cout<<b<<"\t";

}

}


Inline Function

Reduce function call overhead—especially for small functions.

Qualifier inline before a function’s return type in the function definition

“Advises” the compiler to generate a copy of the function’s code in place (when appropriate) to avoid a function call.


Multiple copies of the function code are inserted in the program (often making the program larger).

The compiler can ignore the inline qualifier and typically does so for all but the smallest functions.


Syntax of Inline Function

inline returnType functionName(arguments);

Example:

inline int add(int a, int b);


Program to Illustrate inline Function


#include<conio.h>

inline float mul(float x, float y)

{

return(x*y);

}

inline double div(double p, double q)

{

return(p/q);

}

int main()

{

clrscr();

float a=12.12;

float b=2.2;

cout<<mul(a,b)<<"\n";

cout<<div(a,b)<<"\n";

getch();

return 0;

}


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