﻿ Java - Check whether a number is an Automorphic number or not

# Java: Check whether a number is an Automorphic number or not

## Java Numbers: Exercise-14 with Solution

Write a Java program to check whether a number is an automorphic number or not.

In mathematics, an automorphic number is a number whose square "ends" in the same digits as the number itself. For example, 52 = 25, 62 = 36, 762 = 5776, and 8906252 = 793212890625, so 5, 6, 76 and 890625 are all automorphic numbers.

Test Data
Input a number : 76

Pictorial Presentation: Sample Solution:

Java Code:

``````import java.util.Scanner;
public class Example14 {

public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Input a number : ");
int num = sc.nextInt();
int sq_num = num*num;

String str_num = Integer.toString(num);
String square = Integer.toString(sq_num);

if(square.endsWith(str_num))
System.out.println("Automorphic Number.");
else
System.out.println("Not an Automorphic Number.");
}
}
```
```

Sample Output:

```Input a number : 76
Automorphic 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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