Since the factorial of a number X is the product of the number itself and all its preceding positive integers, we can calculate it using a loop.
We initialize a variable (say fact) to 1, which will hold the running product.
We run a loop from i = 1 to X.
In each iteration, we multiply fact by i (i.e., fact = fact * i).
After the loop ends, fact will contain the factorial of X.

Code

#include <iostream>
using namespace std;

// Function to calculate factorial of a number
int factorial(int X) {
    int ans = 1;

    // Loop from 1 to X to compute factorial
    for (int i = 1; i <= X; i++) {
        ans = ans * i;
    }

    // Return the final result
    return ans;
}

int main() {
    // Input value for which factorial is to be calculated
    int X = 5;

    // Call the factorial function and store the result
    int result = factorial(X);

    // Print the result
    cout << "The factorial of " << X << " is " << result;

    return 0;
}

                            