Factorial of a Number using C

Problem Statement

In this program we will code a basic program to find the factorial of a number in C programming language.

We can do this with the help of

1.    Looping Concept

Code

#include

int factorial(int n)

{

  int fact=1;

  for(int i=1;i<=n;i++)

  {

    fact=fact*i;

  }

  return fact;

}

int main()

{

  int n;

  printf("Enter the number?");

  scanf("%d",&n);

  int res=factorial(n);

  printf("Factorial of %d is : %d",n,res);

  return 0;

}

Output

Enter the number ? - 6

Factorial of 6 is : 720 

Explanation 

Let us consider an example :
Suppose we have to find the factorial of 6,hence this means that we have to calculate 1*2*3*4*5*6. It is clear that we can find the factorial of any number 'n',by multiplying each number from i:1 to 'n', such that fact=fact*i . This can be achieved by using for loop from 1 to 'n'.

Note : It is mandatory for you to initialize the result variable(here fact) with 1 as in an equation ' fact=fact*i ' , if fact=0 then overall result will be 0 as well.