How to Calculate Square and Square Root in Java?

One of the most popular frequently asked Java Interview Questions is, “Given an integer x, write a java program to find the square root of it”. There are many ways to solve this problem. In this article, let’s check out different ways to find square and square root in Java.

1. What is Square and Square Root?

2. How to Square a Number in Java

• By multiplying the number by itself
• Using the Math.pow function

3. How to Find Square Root of a Number in Java

• Using java.lang.Math.sqrt() method
• By using Math.pow() function
• Without using any inbuilt functions

Before discussing the square root code in Java, let’s understand the term square root first.

Square and Square Root

The square of a number is that number times itself. In other terms, when we multiply an integer by itself we call the product the square of the number. Mathematically, the square of a number is given as,

Square of n = n*n

For example, the square of number 4 is 4*4 = 16

The square root is just the opposite of the square. The square root of a number, n, is the number that gives n when multiplied by itself. Mathematically, the square root of a number is given as,

Square Root of n = √ n

Now that you know what square and square root of a number are, let’s see different ways to calculate them in Java.

How to Square a Number in Java?

You can square a number in Java in two different ways:

1. Multiply the number by itself
2. Call theMath.powfunction

Method 1: Square a number by multiplying it by itself

Here’s a Java Program to square a number by multiplying it by itself.

package MyPackage;
import java.util.Scanner;
public class Square1 {
public static void main(String args[]) {
Double num;
Scanner sc= new Scanner(System.in);
System.out.print("Enter a number: ");
num=sc.nextDouble();
Double square = num*num;
System.out.println("Square of "+ num + " is: "+ square);
}
}

Output

Enter a number: 10 Square of 10.0 is: 100.0

Method 2: Square a number with the Math.pow method

Here’s a Java Program to call the Math.pow method to square a number.

package MyPackage;
import java.util.Scanner;
import java.lang.Math;
public class Square2 {
public static void main(String args[]) {
Double num;
Scanner sc= new Scanner(System.in);
System.out.print("Enter a number: ");
num = sc.nextDouble();
Double square = Math.pow(num, 2);
System.out.println("Square of "+ num + " is: "+ square);
}
}

Output

Enter a number: 22 
Square of 22.0 is: 484.0

Now let’s check out how to calculate the square root of a number in Java.

How to Find Square Root of a Number in Java

There are multiple ways to find square root a given number in Java. Let’s explore a few of those.

Method 1: Java Program to Find the square root of a Number using java.lang.Math.sqrt() method

Syntax
public static double sqrt(double x)

1. Parameter: x is the value whose square root is to be returned.

2. Return: This method returns the square root value of the argument passed to it.

• If parameter x is positive double value, this method will return the square root of x
• When x is NaN or less than zero, this method will return NaN
• If parameter x is positive infinity, this method will return positive Infinity
• When x is positive or negative zero, this method will return the result as Zero with the same sign

Code

package MyPackage;
public class SquareRoot2 
{
public static void main(String args[])
{
double a = 100;
System.out.println(Math.sqrt(a));
// Input positive value, Output square root of x
double b = -81.00;
System.out.println(Math.sqrt(b));
// Input negative value, Output NaN
double c = 0.0/0;
// Input NaN, Output NaN
System.out.println(Math.sqrt(c));
double d = 1.0/0;
// Input positive infinity, Output positive infinity
System.out.println(Math.sqrt(d));
double e = 0.0;
// Input positive Zero, Output positive zero
System.out.println(Math.sqrt(e));
}
}

Output

10.0
NaN
NaN
Infinity
0.0

Method 2: Java Program to Find the square root of a Number using java.lang.Math.pow() method

We can use the logic √number = number½ to find the square root of a number.

Code

package MyPackage;
import java.util.Scanner;
public class SquareRoot1 {
public static void main(String[] args)
{
Double num;
Scanner sc= new Scanner(System.in);
System.out.print("Enter a number: ");
num = sc.nextDouble();
Double squareroot = Math.pow(num, 0.5);
System.out.println("The Square of a Given Number  " + num + "  =  " + squareroot);
}
}

Output

Enter a number: 81
The Square of a Given Number 81.0 = 9.0

Method 3: Java Program to Find the square root of a Number without using any in-built method

Here’s the logic that we are using:

The first sqrt number should be the input number / 2. Here’s a Java Program implementing the above logic.

Code

package MyPackage;
public class SquareRoot
{
public static double square(double number){
double t;
double squareroot = number / 2;
do 
{
t = squareroot;
squareroot = (t + (number / t)) / 2;
}
 while ((t - squareroot) != 0);
return squareroot;
}
public static void main(String[] args)
{
double number = 16;
double root;
root = square(number);
System.out.println("Number : "+number);
System.out.println("Square Root : "+root);
}
}

Output

Number : 121.0 
Square Root : 11.0

This brings us to the end of this article.

Make sure you practice as much as possible and revert your experience.

If you wish to check out more articles on the market’s most trending technologies like Artificial Intelligence, DevOps, Ethical Hacking, then you can refer to Edureka’s official site.

Do look out for other articles in this series which will explain the various other aspects of Java.

1. Object Oriented Programming

2. Java Tutorial

3. Polymorphism in Java

4. Abstraction in Java

5. Java String

6. Java Array

7. Java Collections

8. Java Threads

9. Introduction to Java Servlets

10. Servlet and JSP Tutorial

11. Exception Handling in Java

12. Advanced Java Tutorial

13. Java Interview Questions

14. Java Programs

15. Kotlin vs Java

16. Dependency Injection Using Spring Boot

17. Comparable in Java

18. Top 10 Java frameworks

19. Java Reflection API

20. Top 30 Patterns in Java

21. Core Java Cheat Sheet

22. Socket Programming In Java

23. Java OOP Cheat Sheet

24. Annotations in Java

25. Library Management System Project in Java

26. Trees in Java

27. Machine Learning in Java

28. Top Data Structures & Algorithms in Java

29. Java Developer Skills

30. Top 55 Servlet Interview Questions

31. Top Java Projects

32. Java Strings Cheat Sheet

33. Nested Class in Java

34. Java Collections Interview Questions and Answers

35. How to Handle Deadlock in Java?

36. Top 50 Java Collections Interview Questions You Need to Know

37. What is the concept of String Pool in Java?

38. What is the difference between C, C++, and Java?

39. Palindrome in Java- How to check a number or string?

40. Top MVC Interview Questions and Answers You Need to Know

41. Top 10 Applications of Java Programming Language

42. Deadlock in Java

43. Square and Square Root in Java

44. Typecasting in Java

45. Operators in Java and its Types

46. Destructor in Java

47. Binary Search in Java

48. MVC Architecture in Java

49. Hibernate Interview Questions And Answers

Originally published at https://www.edureka.co on September 12, 2019.