﻿ Java - Check whether a number is a Harshad Number or not

# Java: Check whether a number is a Harshad Number or not

## Java Numbers: Exercise-12 with Solution

Write a Java program to check whether a number is a Harshad Number or not.

In recreational mathematics, a harshad number in a given number base, is an integer that is divisible by the sum of its digits when written in that base.
Example: Number 200 is a Harshad Number because the sum of digits 2 and 0 and 0 is 2(2+0+0) and 200 is divisible by 2. Number 171 is a Harshad Number because the sum of digits 1 and 7 and 1 is 9(1+7+1) and 171 is divisible by 9.

Test Data
Input a number : 353

Pictorial Presentation: Sample Solution:

Java Code:

``````import java.util.Scanner;
public class Example12 {

public static void main(String args[])
{
Scanner sc = new Scanner(System.in);

System.out.print("Input a number : ");
int num = sc.nextInt();
int x = num, y, sum = 0;

while(x>0)
{
y = x%10;
sum = sum + y;
x = x/10;
}

if(num%sum == 0)
else
System.out.println(num+" is not a Harshad Number.");
}
}
```
```

Sample Output:

```Input a number : 353
353 is not a Harshad Number.
```

Flowchart: Java Code Editor:

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## Java: Tips of the Day

IsPowerOfTwo

Checks if a value is positive power of two.

To understand how it works let's assume we made a call IsPowerOfTwo(4).

As value is greater than 0, so right side of the && operator will be evaluated.

The result of (~value + 1) is equal to value itself. ~100 + 001 => 011 + 001 => 100. This is equal to value.

The result of (value & value) is value. 100 & 100 => 100.

This will value the expression to true as value is equal to value.

```public static boolean isPowerOfTwo(final int value) {
return value > 0 && ((value & (~value + 1)) == value);
}
```

Ref: https://bit.ly/3sA5d4I

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