A function is a group of statements that together perform a task. Every C program has at least one function, which is main(), and all the most trivial programs can define additional functions.

#include<stdio.h>
float square ( float x ); //function declaration
int main( ) // main function
{
float m, n ;
printf ( "\nEnter some number for finding square \n");
scanf ( "%f", &m ) ;
n = square ( m ) ; // function call
printf ( "\nSquare of the given number %f is %f",m,n );
}
float square ( float x ) // function definition
{
float p ;
p = x * x ;
return ( p ) ;
}

## Output :

Enter some number for finding square
2
Square of the given number 2.000000 is 4.000000

## Algorithm :

- Declare a function.

- Make function call in main function.

- Define the function.

## Comments :