Calculate Log2n without using built-in function

Objective: Given a number n, write a program to calculate Log₂n without using built-in function.

Example:

N = 32
Log₂32 = 5

N = 64
Log₂64 = 6

Approach:

Initialize result = 0.
Keep dividing the given number by 2 till number is greater than 0 and add one to the result if n is greater than equal to 1.

Java Code:

	public class Logn {

	static void computeLogN(int n){
	int result = 0;
	int number = n;
	while(n>0){
	n=n/2;
	if(n>=1)
	result++;
	}
	System.out.println("Log"+number + " value: " + result);
	}

	public static void main(String[] args) {
	int n = 64;
	computeLogN(n);
	}
	}

view raw

logn.java

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Output:

Log64 value: 6