This program takes a positive integer from user and calculates the factorial of that number. Suppose, user enters 6 then,
Factorial will be equal to 1*2*3*4*5*6 = 720
You'll learn to find the factorial of a number using a recursive function in this example.
Visit this page to learn, how you can use loops to calculate factorial.
Example: Calculate Factorial Using Recursion
#include<iostream> using namespace std; int factorial(int n); int main() { int n; cout << "Enter a positive integer: "; cin >> n; cout << "Factorial of " << n << " = " << factorial(n); return 0; } int factorial(int n) { if(n > 1) return n * factorial(n - 1); else return 1; }
Output
Enter an positive integer: 6 Factorial of 6 = 720
In the above program, suppose the user inputs a number 6. The number is passed to the
factorial() function.
In this function, 6 is multiplied to the factorial of (6 - 1 = 5). For this, the number 5 is passed again to the
factorial() function.
Likewise in the next iteration, 5 is multiplied to the factorial of (5 - 1 = 4). And, 4 is passed to the
factorial() function.
This continues until the value reaches 1 and the function returns 1.
Now, each function returns the value back to compute 1 * 2 * 3 * 4 * 5 * 6 = 720, which is returned to the
main() function.