Factorial Program in C

Write a Program to Find the Factorial of a number in C.

Example,

Input: 5
Output: 120

Factorial can be calculated in 2 ways

1. Factorial using Loop (Iteratively)
2. Factorial using recursion (recursively)

Factorial Program in C Using Loop (Iterative method)

We can use for-loop, while-loop or do-while loop.

Factorial Program in C using for-loop

#include<stdio.h>

int main(){
	
	int n, fact, i;
	printf("Enter Number: ");
	scanf("%d",&n);
	
	fact = 1;
	
	for(i=1 ; i<=n ; ++i){
		fact *= i;
	}
	
	printf("Factorial of %d is: %d ", n, fact);
	
	return 0;
}

Factorial Program in C using while-loop

#include<stdio.h>

int main(){
	
	int n, fact, i;
	printf("Enter Number: ");
	scanf("%d",&n);
	
	fact = 1;
	
	while(i<=n){
		fact *= i;
		++i;
	}
	
	printf("Factorial of %d is: %d ", n, fact);
	
	return 0;
}

Factorial Program in C using do-while loop

#include<stdio.h>

int main(){
	
	int n, fact, i;
	printf("Enter Number: ");
	scanf("%d",&n);
	
	fact = 1;
	
	do{
		fact *= i;
		++i;
	}while(i<=n);
	
	printf("Factorial of %d is: %d ", n, fact);
	
	return 0;
}

Output

Factorial Program in C using Recursion (Recursively)

#include<stdio.h>

int fact(int n){
	if(n==0||n==1)
		return 1;
	else
		return n*fact(n-1);
}

int main(){
	
	int n, i;
	printf("Enter Number: ");
	scanf("%d",&n);
	
	printf("Factorial of %d is: %d ", n, fact(n));
	
	return 0;
}

Output

What to study next?

1. Find Maximum Between 3 numbers.
2. Difference between array and linked list.
3. Right-Shift Array by one.