﻿ Java - Check two numbers are Amicable numbers or not

# Java: Check two numbers are Amicable numbers or not

## Java Numbers: Exercise-16 with Solution

Write a Java program to check two numbers are Amicable numbers or not.

Amicable numbers are two different numbers so related that the sum of the proper divisors of each is equal to the other number.
The first ten amicable pairs are: (220, 284), (1184, 1210), (2620, 2924), (5020, 5564), (6232, 6368), (10744, 10856), (12285, 14595), (17296, 18416), (63020, 76084), and (66928, 66992).

Test Data
Input the first number: 220
Input the second number: 284

Pictorial Presentation: Sample Solution:

Java Code:

``````import java.util.Scanner;

public class Example16
{
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
System.out.print("Input the first number: ");
int num1 = in.nextInt();
System.out.print("Input the second number: ");
int num2 = in.nextInt();
int sum_num1 = 0, sum_num2 = 0;
for (int i = 1; i <= num1; i++) {
if (num1 % i == 0)
sum_num1 += i;
}
for (int i = 1; i <= num2; i++) {
if (num2 % i == 0)
sum_num2 += i;
}
if (sum_num1 == sum_num2)
System.out.println("These numbers are amicable.");
else
System.out.println("These numbers are not amicable.");
System.out.println("\n");
}
}
```
```

Sample Output:

```Input the first number: 220
Input the second number: 284
These numbers are amicable.
```

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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