# C program to print factorial of a number

Before write a C program to print factorial of a number, first try to understand what is factorial. Factorial is product of all positive integers in descending orders. Suppose we want to know the factorial of 6.
6! = 6*5*4*3*2*1 = 720
So formula is = n! = n*(n-1)!

## C program to print factorial of a number using for loop – source code

```/*************************************
C program to print factorial of a number

https://bptutorials.com

***************************************/
#include <stdio.h>
#include <conio.h>

void main ()
{
int factorial = 1, i, num;
printf ("Enter Number : ");
scanf ("%d", &num);
for (i = 1; i <= num; i++)
{
factorial = factorial * i;
}
printf ("Factorial of %d is %d", num, factorial);

getch ();
}
```

## Factorial program in C using while loop

```/***********************************************

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factorial program in C using while loop

************************************************/
#include <stdio.h>

void main()
{
int num, fact = 1, i = 1;
printf("Enter a Number : ");
scanf("%d", &num);
while(i<=num)
{
fact = fact*i;
i++;
}
printf("Factorial of %d is : %d ", num, fact);

}
```