Calculate the 2power n where n can be negative

#1

how to write a recursive function which can calculate for negative value of power

#2

@bhaskarkumarindia_194428d5e21261da Here’s how you can write a recursive function in Java to calculate the negative power of a number without using the reciprocal directly:

public class PowerCalculation {

    public static double power(double base, int exp) {
        // Base case
        if (exp == 0) {
            return 1;
        }
        // Recursive case for negative exponent
        else if (exp < 0) {
            return (1 / base) * power(base, exp + 1);
        }
        // Recursive case for positive exponent
        else {
            return base * power(base, exp - 1);
        }
    }

    public static void main(String[] args) {
        System.out.println(power(2, -3));  // Output: 0.125
    }
}

Explanation:

  • Base Case : When exp is 0, the function returns 1, as any number to the power of 0 is 1.
  • Negative Exponent Case : When exp is negative, the function reduces the exponent by 1 (i.e., exp + 1 ) and multiplies the result by 1/base .
  • Positive Exponent Case : When exp is positive, it multiplies the base by the result of the recursive call with exp - 1 .

This Java method will compute the negative power of a number without explicitly using the reciprocal at the start. Instead, it computes the inverse of the base during the recursive steps.