# Do Power in Java

Mohammad Irfan Jan 25, 2021 Dec 09, 2020

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
``````