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Java Exercises: Check whether a given integer is a power of 4 or not

Java Basic: Exercise-110 with Solution

Write a Java program to check whether an given integer is a power of 4 or not.

Given num = 64, return true. Given num = 6, return false.

Pictorial Presentation:

Java Basic Exercises: Check whether a given integer is a power of 4 or not

Sample Solution:

Java Code:

import java.util.Scanner;
public class Example110 {
     public static void main(String[] arg) 
	 {
	   int test = 0;
	   Scanner in = new Scanner(System.in);	
	   System.out.print("Input a positive integer: ");
	   int n = in.nextInt(); 
       if (n < 1) {
			 System.out.print(Boolean.toString(false));
			 test = 1;
		}
		if ((n & (n - 1)) != 0) {
			System.out.print(Boolean.toString(false));
			test = 1;
		}
		if (test==0)
		{
			System.out.print(Boolean.toString((n & 0x55555555) != 0));      	
		}
		System.out.print("\n");
	}	
}

Sample Output:

Input a positive integer: 64                                           
true

Flowchart:

Flowchart: Java exercises: Check whether a given integer is a power of 4 or not

Java Code Editor:

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Previous: Write a Java program to form a staircase shape of n coins where every k-th row must have exactly k coins.
Next: Write a Java program to add two numbers without using any arithmetic operators.

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Java: Tips of the Day

Try and catch:

Java is excellent at catching errors, but it can only recover gracefully if you tell it what to do. The cascading hierarchy of attempting to perform an action in Java starts with try, falls back to catch, and ends with finally. Should the try clause fail, then catch is invoked, and in the end, there's always finally to perform some sensible action regardless of the results. Here's an example:

try {
        cmd = parser.parse(opt, args); 
       
        if(cmd.hasOption("help")) {
                HelpFormatter helper = new HelpFormatter();
                helper.printHelp("Hello ", opt);
                System.exit(0);
                }
        else {
                if(cmd.hasOption("shell") || cmd.hasOption("s")) {
                String target = cmd.getOptionValue("tgt");
                } // else
        } // fi
} catch (ParseException err) {
        System.out.println(err);
        System.exit(1);
        } //catch
        finally {
                new Hello().helloWorld(opt);
        } //finally
} //try

It's a robust system that attempts to avoid irrecoverable errors or, at least, to provide you with the option to give useful feedback to the user. Use it often, and your users will thank you!

Ref: https://red.ht/3EZc9OC