🔀⚡Beginner

Find Factorial of a Number

Calculate n! using loop

Factorial of n (written as n!) is the product of all positive integers from 1 to n.
n! = n × (n-1) × (n-2) × ... × 2 × 1
Special case: 0! = 1

📊 Factorial Examples

= 1

= 120

5×4×3×2×1

= 5040

10!

= 3628800

C Program to Find Factorial

factorial.c

1#include <stdio.h>
2
3int main() {
4    int n;
5    unsigned long long fact = 1;  // Use large type!
6    
7    printf("Enter a number: ");
8    scanf("%d", &n);
9    
10    // Check for negative input
11    if (n < 0) {
12        printf("Factorial not defined for negative numbers\n");
13        return 1;
14    }
15    
16    // Calculate factorial using loop
17    for (int i = 1; i <= n; i++) {
18        fact *= i;  // fact = fact * i
19    }
20    
21    printf("%d! = %llu\n", n, fact);
22    
23    return 0;
24}