Last Updated on July 17, 2024 by Abhishek Sharma

Checking whether a number is a perfect square is a fundamental operation in mathematics and programming. A perfect square is an integer that is the square of another integer. In this guide, we’ll explore how to implement a Java program to determine if a given number is a perfect square, covering different approaches and considerations for efficient implementation.

## What is the Perfect Square?

A positive integer that is the square of another positive integer is known as a perfect square or square number. In other words, the perfect square is the result of multiplying two identical integers together. In a nutshell, it is either the product of an integer with itself or the product of two positive equal integers. For example, 1, 4, 9, 16, 25, and so on are perfect squares because they can be expressed as the square of an integer (1^2, 2^2, 3^2, 4^2, 5^2, etc.).

## Ways to Check for the Perfect Square

We have different ways to check if a number is a perfect square or not.

### Using User-Defined Logic

Approach to check using sqrt() method

**Step 1:**The program first prompts the user to enter a number to be checked if it is a perfect square.**Step 2:**The isPerfectSquare() method is executed and then loops through all numbers from 1 to the square root of the input number and checks if the square of any of those numbers is equal to the input number.**Step 3:**If a number is found whose square is equal to the input number, the method returns true indicating that the input number is a perfect square. Otherwise, it returns false.

**Code Implementation**

class PerfectSquareChecker { public static void main(String[] args) { int number = 324; if (isPerfectSquare(number)) { System.out.println(number + " is a perfect square."); } else { System.out.println(number + " is not a perfect square."); } } public static boolean isPerfectSquare(int number) { for (int i = 1; i * i <= number; i++) { if (i * i == number) { return true; } } return false; } }

**Output**

`324 is a perfect square.`

### Using Sqrt()

Approach to check using sqrt() method

**Step 1:**Find the provided number’s square root first.**Step 2:**The square root’s floor value must be determined.**Step 3:**Discover the discrepancy between the floor value and the square root that was discovered in Step 1.**Step 4:**Compare the value (that we obtained in step 3) to 0 to finish. The provided integer is a perfect square if the value is 0, else it is not.

For example,

For the number 324, we do the following approach.

- 18 is the square root of 324.
- The square root’s floor value is equal to 18.
- Square root and floor values vary by zero. Hence, the number is a perfect square.

**Code Implementation**

class PerfectSquareChecker { static boolean checkPerfectSquare(double number) { double sqrt=Math.sqrt(number); return ((sqrt - Math.floor(sqrt)) == 0); } public static void main(String[] args) { double number= 324; if (checkPerfectSquare(number)) System.out.print("The given number is perfect square."); else System.out.print("The given number is not perfect square."); } }

**Output**

`The given number is perfect square.`

**Conclusion**

Implementing a Java program to check for perfect squares involves leveraging mathematical properties or computational methods to efficiently determine if a number is a perfect square. Whether validating input for algorithms or performing mathematical computations, this capability enhances the functionality and utility of Java programs. By mastering perfect square checks, developers can ensure accurate and efficient handling of numerical data.

## Frequently Asked Questions related to Java Program to Check for the Perfect Square:

Here are some FAQs related to Java Program to Check for the Perfect Square:

**1. How can I check if a number is a perfect square in Java?**

You can check if a number is a perfect square in Java by calculating its square root and verifying if squaring this root yields the original number.

**2. What is the mathematical approach to determine if a number is a perfect square?**

The mathematical approach involves computing the integer square root of the number and checking if squaring this root equals the original number.

**3. Can negative numbers be perfect squares?**

No, by definition, perfect squares are non-negative integers. Therefore, negative numbers cannot be perfect squares.

**4. What is the time complexity of checking for a perfect square using the mathematical approach?**

The time complexity of checking for a perfect square using the mathematical approach is O(1), as it involves a single square root calculation and a simple comparison.

**5. Are there other approaches besides the mathematical method to check for perfect squares?**

Yes, alternative methods include using binary search for optimization or iterating through possible square roots. Each approach has its advantages depending on the context and size of the number.