Java: Solve quadratic equations

Last update on April 10 2025 05:38:07 (UTC/GMT +8 hours)

Solve Quadratic Equation

Write a Java program to solve quadratic equations (use if, else if and else).

Test Data
Input a: 1
Input b: 5
Input c: 1

Pictorial Presentation:

Sample Solution:

Java Code:

import java.util.Scanner;
public class Exercise2 {

    
  public static void main(String[] Strings) {

        Scanner input = new Scanner(System.in);

            System.out.print("Input a: ");
            double a = input.nextDouble();
            System.out.print("Input b: ");
            double b = input.nextDouble();
            System.out.print("Input c: ");
            double c = input.nextDouble();

            double result = b * b - 4.0 * a * c;

            if (result > 0.0) {
                double r1 = (-b + Math.pow(result, 0.5)) / (2.0 * a);
                double r2 = (-b - Math.pow(result, 0.5)) / (2.0 * a);
                System.out.println("The roots are " + r1 + " and " + r2);
            } else if (result == 0.0) {
                double r1 = -b / (2.0 * a);
                System.out.println("The root is " + r1);
            } else {
                System.out.println("The equation has no real roots.");
            }

    }
}

Sample Output:

Input a: 1                                                                                                    
Input b: 5                                                                                                    
Input c: 2                                                                                                    
The roots are -0.4384471871911697 and -4.561552812808831

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to solve a quadratic equation and display real roots, complex roots, or a message if no real roots exist.
• Write a Java program to accept quadratic coefficients from command line arguments and output the roots with formatted precision.
• Write a Java program to compute the discriminant and use a ternary operator to determine the type of roots.
• Write a Java program to solve quadratic equations using lambda expressions for computing the discriminant and roots.

Java Code Editor:

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