Answer:
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;
}
