# Java Program to Calculate the Power of a Number

In this java program, we will learn about how to calculate the power of a number using loops, using Math.pow() method and using recursion.

To calculate the power of a number(AN) we repetitively multiply base number(A) to inself up to exponent(N) times.
For Example

```AN = A*A*A*A..... N times
A5 = A*A*A*A*A
```

To understand this java program, you should have understanding of the following Java programming concepts:

## Java Program to calculate power of a number using a loop

```public class PowerOfNumberLoop {
public static void main(String[] args) {
int base = 2, exponent = 6, result = 1;

for( int i = 1; i <= exponent ; i++) {
result = result * base;
}
System.out.println("2^6 = " +result);
}
}
```
Output
```2^6 = 64
```

Using the for loop, we multiplying the result by base up to exponent times.

## Java Program to calculate power of a number using recursion

```public class PowerOfNumberRecursion {
// Function to calculate A^N
static int power(int base, int exponent) {
if (exponent == 0)
return 1;
else
return base * power(base, exponent-1);
}

public static void main(String[] args) {
System.out.println("2^6 = " + power(2, 6));
}
}
```
Output
```2^6 = 64
```

In above java program, we are using following recurrence relation to calculate AN.

```AN = A*A*A*A..... N times
AN = A * AN-1
```
Let power(A, N) is a function to calculate AN. As per the above recurrence equation, To find power(A, N) we can first calculate power(A, N-1) then multiply it with A. power(A, N) = A * power(A, N-1)

## Java Program to calculate power of a number using Math.pow() method

```public class PowerOfNumberPowMethod {
public static void main(String[] args) {
int base = 2, exponent = 6;

double result = Math.pow(base, exponent);
System.out.println("2^6 = " +result);
}
}
```
Output
```2^6 = 64.0
```

In this program, we use Java's Math.pow() function to calculate the power of a number.