Funtion in C Language

Function in C Language :

                                                  

 Function 

function is a block of code or set of statement to performs some specific task is called function.

why  be use  function:

• Reusebility code
• Reduce complexity
• Reduce size of code
• Easily debugging(error find)
• Reduce duplicate

Types of  function :

• 1-Predefined function
• 2-User defined function

1- Predefined funtion:

Library functions in C language are inbuilt functions is called 

predefined funtion.

• Library function
• Scanf()
• printf()
• clrscr()
• declaration in header files

2- User defined function:

user defined function are self contained block of statement which

are written by the user to compute or perform a task.

User defined function make a program.

return type   function name (list of argument)

         int sum(int a ,int b)

No return value 

program using void return type

Note :

• always return some value 
• use return keyword inside function 
• can use in expression

Not follow 

example:

#include<stdio.h>

#include<conio.h>

void sum(int a,int b)

{

int c=a+b;

printf(" %d",c);

}

void main()

{

sum(3,5);

getch();

}

output 

8

Return value 

program using int return type

Note:

• always return some value 
• use return keyword inside function 
• can use in expression

yes follow three step:

example:

#include<stdio.h>

#include<conio.h>

int sum()  // declaration

{

int a=10,b=20;

int c=a+b;

return c;

}

void main()

{

int x=sum();// calling

printf("%d",x);

getch();

}

output 

30