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(A^N) 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:

• For Loop in Java
• Recursion in Java

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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.

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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 A^N.

AN = A*A*A*A..... N times
AN = A * AN-1

Let power(A, N) is a function to calculate A^N. 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)

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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.

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