# Write a program in C to calculate the factorial of a number

Posted in  Vinay Khatri
Last updated on June 9, 2022

Here in this program, we will code to calculate the factorial of a number entered by the user. Read on Factorial Program in C.

## What is a factorial?

It is a mathematic concept mostly used in permutation, combination, and probability, its symbol is (!). In simple words, a factorial says multiply all whole numbers from our chosen number down to 1. For example, if we say 5 factorials in math it would be represented by 5! and evaluated by 5*4*3*2*1 = 120. By convention, the 0! is equal to 1.

### Use/Application of Factorial

• In recursion we use Factorial
• In permutation
• In combination
• In probability distribution

### C statements we will use in the program:

• For loop
• * (multiplication arithmetic operator)

### Factorial Program in C Language

```#include<stdio.h>
#include<conio.h>
void main()
{
long num, i,fact=1;
clrscr();
printf("Enter a number:");
scanf("%ld",&num);
for(i=num; i>=1; i--)
{ fact*=i;
}
printf("The factorial of the number %ld is %ld",num,fact);
getch();
}```

Output:

```Enter a number:10
The factorial of the number 10 is 3628800```