## Factorial Program In C

Factorial Program in C: Factorial of n is the product of all positive descending integers. Before going to see factorial program in c we will see what is the factorial means. lets see what is concept of factorial number-

### What is a Factorial Number

factorial number is nothing but the multiplication of all smaller  numbers of that particular number including itself. for better understanding see the following example-

if we want to ascertain 5!(factorial of 5) then,

5!=5*4*3*2*1

means 5!=120.(factorial of 5 is 120)

(note: factorial is denoted by '!' mark.)

we can write factorial program using many ways ,but here we will see the programs using for loop,while loop and c factorial program using function recursion.

### C factorial Program : Using For loop

#include<stdio.h>

void main()

int num,i;

int fact=1;

printf("Enter a number To Find Out Factorial: ");

scanf("%d",&num);

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

fact=fact*i;

}

printf("The Factorial of %d is: %d",num,fact);

getch();

Output:

Enter a number To Find Out Factorial: 4

The Factorial of 5 is: 24

#### C Factorial Program: Using While Loop

#include<stdio.h>

# include<conio.h>

void main()

{

int num,fact=1,copyno=0;

printf("Enter Number To Findout Factorial:");

scanf("%d",&num);

copyno=num;

while(num>0)

{

fact=fact*num;

num--;

}

printf("Factorial of %d is:%d",copyno,fact);

getch();

}

Output:

Enter Number To Findout Factorial:3

Factorial of 3 is :6

### C Factorial Program : Using Function Recursion

#include<stdio.h>

long fact(int n)

{

if (num == 0)

return 1;

else

return(num * factorial(num-1));

}

void main()

{

int num;

long factNum;

printf("Enter a number To Find Out Factorial: ");

scanf("%d", &num);

factNum = fact(num);

printf("Factorial of %d is %ld\n", num, factNum);

getch();

Output:

Enter a number To Find Out Factorial: 5

Factorial of 5 is: 120