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C++ Program to Find Factorial

by Anup Maurya
23 minutes read

In this article, you’ll learn about how to make C++ Program to Find Factorial.

What is the factorial of a number?

Factorial of a non-negative integer is the multiplication of all positive integers smaller than or equal to n, i.e. factorial of 5 is 5*4*3*2*1 which is 120. 

The factorial of a negative number doesn’t exist. And the factorial of 0 is 1.

Program to find the factorial of a given number using for loop

#include <iostream>
using namespace std;

int main() {
    int n;
    long factorial = 1.0;

    cout << "Enter a positive integer: ";
    cin >> n;

    if (n < 0)
        cout << "Error! Factorial of a negative number doesn't exist.";
    else {
        for(int i = 1; i <= n; ++i) {
            factorial *= i;
        cout << "Factorial of " << n << " = " << factorial;    

    return 0;


Enter a positive integer: 4
Factorial of 4 = 24

In the above program, we take a positive integer from the user and compute the factorial using for loop. We print an error message if the user enters a negative number.

Program to find the factorial of a given number using recursion

#include <iostream>
using namespace std;

int fact(int n){
        return n*fact(n-1);
    return 1;
int main() {
    int num;
    cin>>"Enter an integer to compute the factorial "
    return 0;

A factorial is represented by a number and a  ” ! ”  mark at the end. It is widely used in permutations and combinations to calculate the total possible outcomes. A French mathematician Christian Kramp firstly used the exclamation.

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