C program example for factorial:

What is factorial of a number?

Factorial is denoted by the symbol ‘!’. For example, factorial of a number 4 is denoted as 4!. Factorial of a number is defined as the product of “the number and all integers less than that number except zero and negative integers”.
Natural numbers ( non-negative integers ) which are greater than zero are used for factorial concept.

Factorial Example:

Zero factorial (0!) = 1
one factorial (1!) = 1
Two factorial (2!) = 2*1 = 2
Three factorial (3!) = 3*2*1 = 6
Four factorial (4!) = 4*3*2*1 = 24
Five factorial (5!) = 5*4*3*2*1 = 120
etc…

The common mathematical formula for finding factorial of the number ‘n’ is given below.

n! = n ( n – 1)( n – 2)( n – 3) …… (1)

Example C program for factorial:

#include <stdio.h>
int main()
{
   int i,fact=1,num;
 
   printf("\nPlease enter a number to find factorial : ");
   scanf("%d",&num);
 
   if (num<0)
   {
      printf("\nPlease enter a positive number to");
      printf(" find factorial and try again. \n");
      printf("\nFactorial can't be found for negative");
      printf(" values. It can be only positive or 0 \n");
      return 1;
   } 
 
   for(i=1;i<=num;i++)
   fact=fact*i;
   printf("\n");
   printf("Entered number is %d and it's factorial (%d!) is %d\n",num,num,fact);
   return 0;
}

#include <stdio.h>

int main()

{

int i,fact=1,num;

printf("\nPlease enter a number to find factorial : ");

scanf("%d",&num);

if (num<0)

{

printf("\nPlease enter a positive number to");

printf(" find factorial and try again. \n");

printf("\nFactorial can't be found for negative");

printf(" values. It can be only positive or 0 \n");

return 1;

}

for(i=1;i<=num;i++)

fact=fact*i;

printf("\n");

printf("Entered number is %d and it's factorial (%d!) is %d\n",num,num,fact);

return 0;

}

Output of C program for factorial:

Please enter a number to find factorial : 7
Entered number is 7 and it’s factorial (7!) is 5040

OTHER C PROGRAMS:

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