What is function in C-programming language?


Function in c
Function In C


A Function in c programming language is a block of code which only runs when it is called. Every C-Program contains at-least one function which is main().

We can pass inputs as parameters, into a function.
Functions are made to perform some actions whenever it is called.
We can call a function several times in a program.



There are two types of functions available in C-Programming Language:


Functions which are predefined in C-Library. Like printf(), scanf(), main()...etc.


Functions which are defined by user are called user-defined functions.

How to Declare A Function in C-Programming Language?

Return_type function_Name(parameters)
{
    block of code...
}

Return Type : A function may return a value. The return-type is the data type of the value, the function returns. Some functions perform the desired operations without returning a value. In this case, the return-type is the keyword void.

Function-Name :This is the actual name of the function. The function name and the parameter list together constitute the function signature.

Parameters :A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter. This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters.

Block Of Code :The block of code contains a collection of statements that define what the function does.

example :

void myfun()
{
    printf("I am a function");
}

How to call a function in C-Programming Language?

Function-Name(parameters);

example :

myfun();

Example with a program :

#include<stdio.h>
int main()
{
int a = 5, b = 6;
int c = add(a,b);
printf("The sum of %d and %d is %d\n",a,b,c);
return 0;
}
int add(int x, int y)
{
return x+y;
}

Output :

The sum of 5 and 6 is 11

Function with void return value :


void hello()
  {
    printf("Hello i'm a function");
  }

Function With int return value :


int hello()
  {
    printf("Hello i'm a function");
    return 0;
  }

Function with double return value :


double hello(double a)
  {
    a = 9.9;
    return a;
  }

Function with parameters :


int add(int a, int b)
  {
  return a+b;
  }