Write a program that lets the user enter a nonnegative integer and then uses a loop to calculate the factorial of that number. Print the factorial to standard output

In C++:

#include <iostream>

using namespace std;

int main(){

   int num,fact=1;

   cout<<"Positive integer: ";

   cin>>num;

   if(num<0){

   cout<<"Positive integers only";

   }

   else{

       for(int i =1;i<=num;i++){

       fact*=i;

       }

       cout<<num<<"! = "<<fact;

   }

   return 0;

}

Explanation:

This line declares num and fact as integer. It also initializes fact to 1

   int num,fact=1;

This line prompts the user for a positive integer

   cout<<"Positive integer: ";

This line gets input from user

   cin>>num;

This line checks if input is negative

   if(num<0){

If input is negative, This line prints the following message

   cout<<"Positive integers only";

   }

   else{

If input is positive or 0; The following iteration calculates the factorial

       for(int i =1;i<=num;i++){

       fact*=i;

       }

This prints the calculated factorial

       cout<<num<<"! = "<<fact;

   }