Square Root Without Inbuilt Functions Example in Java

Introduction

Square Root Without InBuilt Functions is a classic Java console program that demonstrates the concept with complete source code and sample output. Calculation programs apply formulas to solve geometry, statistics and numeric problems.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

A square root of a number a is a number y such that y2 = a, in other words, a number y whose square (the result of multiplying the number by itself, or y * y) is a. For example, 4 and /4 are square roots of 16 because 4^2 = (/4)^2 = 16.

Square Root Without InBuilt Functions Example Program

import java.util.Scanner;
public class SquareRootWithoutInBuilt{
    public static void main(String[] args){
	Scanner in=new Scanner(System.in);
	System.out.print("Enter the number for which Square root is to be found: ");
        double num =in.nextInt();
        squareRootMethod(num);
    }
    public static void squareRootMethod(double num){
        boolean checkpos = true;
        double numm;
        if(num==0){
            System.out.println("Square root of "+num+" = "+0);
        }
        else if(num<0){
            num=-num;
            checkpos = false;
        }
        double squareRoot = num/2;
        do{
            numm=squareRoot;
            squareRoot = (numm + (num/numm))/2;
        }while((numm-squareRoot)!=0);
        if(checkpos){
            System.out.println("Square roots of "+num+" are ");
            System.out.println("+"+squareRoot);
            System.out.println("-"+squareRoot);
        }
        else{
            System.out.println("Square roots of -"+num+" are ");
            System.out.println("+"+squareRoot+" i");
            System.out.println("-"+squareRoot+" i");
        }
    }
}

Sample Output

output is
Enter the number for which Square root is to be found: 2
Square roots of 2.0 are
+1.414213562373095
-1.414213562373095

When to use

Use these formulas in homework tools, engineering calculators or anywhere repeated numeric computation is needed.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.Scanner; imports a class used later in the program.

3. A Scanner reads typed input from the keyboard (System.in).

4. A println / print call writes text to the console — part of the sample output below.

5. double num =in.nextInt(); updates a variable used in the calculation or output.

6. boolean checkpos = true; updates a variable used in the calculation or output.

7. The if statement runs the nested code only when the condition is true.

8. A println / print call writes text to the console — part of the sample output below.

Best Practices

Common Mistakes