Write a C program to find a factorial of a given number

Article by: Manish Methani

Last Updated: September 27, 2021 at 10:04am IST
1 min 32 sec

Factorial of a given number is defined as the product of a given number with its previous number till that number reaches 1. In mathematical representation, factorial is represented by !

Factorial of 5! is 

5*4*3*2*1 = 120 

Factorial of a number without using user defined function

#include
int main()
{
  int number = 5,i;
  long int factorial;
  factorial = 1;
  for(i = number; i >= 1; i--)
  { 
     factorial = factorial * i;
     printf("
Factorial of %d is = %ld", number, factorial);
     return 0;
  }

Output

Factorial of 5 is = 120

Factorial of a number using user defined function

#include
long int factorial(int n)
{
   int i;
   long int factorial = 1;
   if(n==1) return factorial;
   for(i = n; i >= 1;i--)
   {
     factorial = factorial * i;
     return factorial;
   }
}
int main()
{
  int number = 5;
  printf("
Factorial of %d is = %ld",number,factorial(number));
  return 0;
}

Output

Factorial of 5 is = 120

Factorial of a number using recursion

#include
long int factorial(int n)
{
   if(n==1) return 1;
   return n*factorial(n-1);
}

int main()
{
  int number = 5;
  printf("Factorial of %d is = %ld",number,factorial(number));
  return 0;
}

Output

Factorial of 5 is = 120