Factorial of a Number
Program to calculate factorial of a number
BeginnerTopic: Loop Programs
C++ Factorial of a Number Program
This program helps you to learn the fundamental structure and syntax of C++ programming.
#include <iostream>
using namespace std;
int main() {
int n;
long long factorial = 1;
cout << "Enter a positive integer: ";
cin >> n;
if (n < 0) {
cout << "Factorial is not defined for negative numbers" << endl;
} else {
for (int i = 1; i <= n; i++) {
factorial *= i;
}
cout << "Factorial of " << n << " = " << factorial << endl;
}
return 0;
}Output
Enter a positive integer: 5 Factorial of 5 = 120
Understanding Factorial of a Number
Factorial of n (n!) is the product of all positive integers from 1 to n. We use long long to handle large factorials. The program multiplies numbers from 1 to n iteratively. We also check for negative input as factorial is only defined for non-negative integers.
Note: To write and run C++ programs, you need to set up the local environment on your computer. Refer to the complete article Setting up C++ Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your C++ programs.