﻿ Java - Check a number is a cube or not

# Java: Check a number is a cube or not

## Java Numbers: Exercise-18 with Solution

Write a Java program to check if a number is a cube or not.

In arithmetic and algebra, the cube of a number n is its third power: the result of the number multiplied by itself twice:
n3 = n × n × n
Input Data:
Input a number: 8

Pictorial Presentation: Sample Solution:

Java Code:

``````import java.util.Scanner;
public class Example18 {

public static void main( String args[] ){
Scanner sc = new Scanner( System.in );
System.out.print("Input a number: ");
int num = sc.nextInt();
int n = (int) Math.round(Math.pow(num, 1.0/3.0));
if((num == n * n * n))
{
System.out.print("Number is a cube.");
}
else
{
System.out.print("Number is not a cube.");
}
System.out.println("\n");
}
}
```
```

Sample Output:

```Input a number: 8
Number is a cube.
```

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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