c++ program on factorial of a number in short

Sure, here is a simple C++ program to calculate the factorial of a number:

#include<iostream>
using namespace std;

int factorial(int n) {
    if(n > 1)
        return n * factorial(n - 1);
    else
        return 1;
}

int main() {
    int num;
    cout << "Enter a positive integer: ";
    cin >> num;
    cout << "Factorial of " << num << " = " << factorial(num);
    return 0;
}

Here's how it works:

1. The factorial function is a recursive function that multiplies the number by the factorial of the number minus one, until it gets to 1 (since the factorial of 1 is 1).

2. In the main function, we ask the user to enter a number.

3. We then call the factorial function with the user's number, and print out the result.