Java program to find the factorial of a number using recursion

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In this program, you will learn how to use recursive functions in Java to find and display the factorial of a number.

The factorial of a positive number n is given by the following formula:

factorial of n (n!) =　1　*　2　*　3　*　4　*　...　*　n

The factorial of a negative number does not exist. The factorial of 0 is1.

In this example, you will learn how to use recursion to find the factorial of a number. Visit this page to learn howUsing a loop to find the factorial of a number.

Example: Using recursive factorial

public class Factorial {
　　　　public static void main(String[] args) {
　　　　　　　　int num =　6;
　　　　　　　　long factorial = multiplyNumbers(num);
　　　　　　　　System.out.println("")　+　num　+　"Factorial = "　+　factorial);
　　　　}
　　　　public static long multiplyNumbers(int num)
　　　　{
　　　　　　　　if (num >=　1)
　　　　　　　　　　　　return num　*　multiplyNumbers(num　-　1);
　　　　　　　　else
　　　　　　　　　　　　return　1;
　　　　}
}

When the program is run, the output is:

　6Factorial =　720

Initially, multiplyNumbers() is called from the main() function, with6Passed as a parameter.

In each recursive call, the value of the parameter num is reduced1Until num is less than1.

When the value num is less than1There will be no recursive calls.

Each recursive call returns to us:

6　*　5　*　4　*　3　*　2　*　1　*　1　(for 0) =　720

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