Java program to find the power of a number using recursion

Java program to find the power of a number using recursion:

This post will show you how to find the power of a number using a recursive function in Java. The program will take the base and power values as inputs from the user to calculate the power.

Recursive function:

In simple word, a recursive function calls itself. Normally, we use a recursive function with a value to find a result. It calls itself again and again with a new value and it stops at a specific value.

For example,

int getSum(int no){
    if(no == 0) return 0;
    return no + getSum(no - 1);
}

The getSum is a recursive function and it can find the sum of all numbers from 1 to no.
It returns no + getSum(no - 1), i.e. it calls itself again with no - 1.
This will return (no - 1) + getSum(no - 1 - 1). So, the final return will be no + (no - 1) + getSum(no - 1 - 1). It will keep calling itself again and again until the value of no become 0.
It will return 0 if no is zero, i.e. the recursion will stop.

Recursive way to find the power of a number:

If n is the number and p is the power, the power of the number n can be found by multiplying n to itself for p number of times. We can use a recursive function to find that.

The function will take the number and the power values as the parameters.
On each recursive call, it will decrement the value of the power by one. It will return the result of multiplying itself with the result of its recursive call.
The recursion will stop once the power become 0.

Below is the complete program:

import java.util.Scanner;

class Main {
    static int findPower(int base, int power) {
        if (power == 0) return 1;
        return base * findPower(base, power - 1);
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int base, power;

        System.out.println("Enter the base: ");
        base = scanner.nextInt();

        System.out.println("Enter the power: ");
        power = scanner.nextInt();

        System.out.println(base + "^" + power + " = " + findPower(base, power));
    }
}

Here,

We created a Scanner object, scanner to read the user input values.
The integer variables base and power are used to store the base and power values.
It asks the user to enter the base and power. It uses the scanner object to read these values and assigns to the base and power integer variables.
The findPower method is used to find the power. It takes the base and power values as its parameters and returns the power.
It returns base * findPower(base, power - 1). On each step, it calls the findPower method recursively. The recursive calls stops and returns 1 when the power becomes 0.

If you run this program, it will print output as below:

Enter the base: 
3
Enter the power: 
4
3^4 = 81

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Java program to find the power of a number using recursion