How to Do Power in Java

This tutorial introduces how to do power operation in Java and lists some example codes to understand the topic.

To raise a number to a power in Java, we can use the pow() method of the Math class or our own custom code that uses loop or recursion technique. Let’s see some examples.

Raise a Number to a Power Using the pow() Method in Java

The pow() method belongs to the Math class in Java used to generate a number of the given power. It is a simple and straightforward approach because pow() is a built-in method that reduces the effort to write custom code. See the example below.

public class SimpleTesting {
  public static void main(String[] args) {
    double a = 20;
    double power = 2;
    double result = Math.pow(a, power);
    System.out.println(a + " power of " + power + " = " + result);
  }
}

Output:

20.0 power of 2.0 = 400.0

Raise a Number to Power Using the while Loop in Java

If you don’t want to use the built-in pow() method, then use the custom code below. We use a while loop inside this code to generate a number to a power. See the example below.

public class SimpleTesting {
  public static void main(String[] args) {
    double a = 20;
    double power = 2;
    double result = 1;
    double temp = power;

    while (temp != 0) {
      result *= a;
      --temp;
    }
    System.out.println(a + " power of " + power + " = " + result);
  }
}

Output:

20.0 power of 2.0 = 400.0

Raise a Number to Power Using the for Loop in Java

If you don’t want to use the built-in pow() method, use the custom code below. We use the for loop inside this code to generate a number to a power. See the example below.

public class SimpleTesting {
  public static void main(String[] args) {
    double a = 20;
    double power = 2;
    double result = 1;
    double temp = power;

    for (; temp != 0; --temp) {
      result *= a;
    }
    System.out.println(a + " power of " + power + " = " + result);
  }
}

Output:

20.0 power of 2.0 = 400.0

Raise a Number to a Power Using the recursion in Java

This is another approach where we can use recursion to raise a number to a power in Java. Recursion is a technique in which a function calls itself repeatedly until the base condition meets. Here, we create a recursion method, pow(). See the example below.

public class SimpleTesting {
  static double result = 1;
  static void pow(double n, double p) {
    if (p <= 0) {
      return;
    } else if (n == 0 && p >= 1) {
      result = 0;
      return;
    } else
      result = result * n;
    pow(n, p - 1);
  }
  public static void main(String[] args) {
    double a = 20;
    double power = 2;
    pow(a, power);
    System.out.println(a + " power of " + power + " = " + result);
  }
}

Output:

20.0 power of 2.0 = 400.0