Java Program to Check for the Perfect Square

Last Updated on May 15, 2023 by Prepbytes

We will learn how to check for perfect squares in the Java programming language on this page. When given an integer number, we must output "True" if it is true and "False" otherwise.

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
In conclusion, to check whether a given number is a perfect square, there are several methods available. One way is to take the square root of the number and check whether the result is an integer or not. Another method is to factorize the number and check whether all of its factors are paired up or not. Additionally, there are some mathematical tricks, such as the digital root test and the modular arithmetic test, that can be used to quickly determine whether a number is a perfect square or not. Ultimately, the best method to use will depend on the specific situation and the available tools.

Frequently Asked Questions

Q1. What is a perfect square?
Ans. A perfect square is a number that can be expressed as the product of a whole number multiplied by itself.

Q2. How do I check if a number is a perfect square?
Ans. There are several ways to check if a number is a perfect square. One way is to take the square root of the number and check if the result is an integer. Another method is to factorize the number and check if all of its factors are paired up. There are also mathematical tricks, such as the digital root test and the modular arithmetic test, that can be used to quickly determine whether a number is a perfect square.

Q3. Can all positive integers be expressed as perfect squares?
Ans. No, not all positive integers can be expressed as perfect squares. For example, the number 2 cannot be expressed as a perfect square.

Q4. What is the largest perfect square that can be represented using a 32-bit integer?
Ans. The largest perfect square that can be represented using a 32-bit integer is 2,147,483,648 (which is equal to the square of 46,340).

Q5. How are perfect squares used in mathematics?
Ans. Perfect squares are used in a variety of mathematical contexts, including geometry, algebra, and number theory. They are particularly important in the study of Pythagorean triples and in calculating areas of squares and other shapes.