Find the Factorial of a Number: C

This video tutorial illustrates finding factorial of a given number using C programming.

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.

Ex:
if user enters 5, then the factorial is 1 * 2 * 3 * 4 * 5 i.e., factorial = 120
This logic must be handled with a c program.

Full Source Code

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#include < stdio.h >
#include < conio.h >
 
void main()
{
int num, i, fact = 1;
clrscr();
 
printf("Enter a number\n");
scanf("%d", &num);
 
for( i = 1; i < = num; i++ )
 fact = fact * i;                // fact *= i;
 
printf("\nFactorial of %d is %d", num, fact);
 
getch();
 
}

Here the for loop stars from 1 and not 0. As anything multiplied by 0 would also be zero.

Note: Factorial of 0 is 1. i.e., 0! = 1

fact *= i; is the compact representation of fact = fact * i;

Video Tutorial: Factorial in c

Output:
Enter a number
5
Factorial of 5 is 120

Also Watch/Read: Find the Factorial of a Number: C++