
Problem Statement: Given a number N, find the factorial of the number. Factorial program in C.
Examples:
Example 1: Input: N = 4 Output: 24 Explanation: 4*3*2*1 = 24 Example 2: Input: N = 5 Output: 120 Explanation: 5*4*3*2*1 = 120
Disclaimer: Don’t jump directly to the solution, try it out yourself first.
What is factorial of a number?
Factorial of a number is defined as the product of all positive numbers less than or equals to that number. As given in the above examples, factorial of 4 will be product of all numbers less than or equal to 4. That is, 1,2,3,4.
Therefore, factorial of 4 = 1*2*3*4 = 24.
In mathematics, factorial is defined by the sign “!”. That is, factorial of 4 will be denoted as “4!”
Approach:
We will run a loop from 1 to the given number and multiply each number in that range then the resultant product is our factorial.
Code:
C Program
#include <stdio.h>
int factorial(int n) {
int ans = 1;
for (int i = 1; i <= n; i++) {
ans = ans * i;
}
return ans;
}
int main() {
int n = 5;
int result = factorial(n);
printf("The factorial of %d is %d",n,result);
}
Output: The factorial of 5 is 120
Time Complexity: O(n)
Space Complexity: O(1)
Special thanks to Subhrajit Das for contributing to this article on takeUforward. If you also wish to share your knowledge with the takeUforward fam, please check out this article