Understanding the Java Float Equals Method

Introduction

In Java, the Float class has an equals() method, which helps in comparing the equality of two float values. In this lab, we will learn about the implementation, syntax, and various examples of the method.

Setting up the class file

We will first create a Java file in the ~/project directory. Let's name it FloatEquals.java.

cd ~/project
touch FloatEquals.java

Implementing the `equals()` method

We will write the equals() method inside the main method of our FloatEquals.java. Then, we will create two Float objects and compare them using the equals() method. Finally, we will print the result to the console.

Add the following code to the FloatEquals.java file:

public class FloatEquals {
    public static void main(String[] args) {
        // Implementing the equals() method
        Float num1 = 10.5f;
        Float num2 = 10.5f;
        boolean equal = num1.equals(num2);
        System.out.println("Are num1 and num2 equal? " + equal);
    }
}

Explanation: Here, we have created two Float objects, num1 and num2, and set them both equal to 10.5f. Then, we have compared them using the equals() method, and stored the result in a boolean variable called equal. Finally, we have printed the result to the console using the println() method, by concatenating the result with a string.

Providing different values to the `equals()` method

Now that we have implemented the method for Float objects, let's allow the user to provide two different Float values to compare them using the equals() method.

Replace the code you added to the main method of FloatEquals.java with the following code:

import java.util.Scanner;

public class FloatEquals {
    public static void main(String[] args) {
        // Providing different values to the equals() method
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter value 1: ");
        Float num1 = sc.nextFloat();
        System.out.print("Enter value 2: ");
        Float num2 = sc.nextFloat();
        boolean equal = num1.equals(num2);
        System.out.println("Are the values equal? " + equal);
    }
}

Explanation: Here, we are taking two Float values as input from the user, using the Scanner class and its nextFloat() method. We are then comparing them using the equals() method, and storing the result in a boolean variable called equal. Finally, we are printing the result to the console using the println() method, by concatenating a string with the result.

Handling errors with try-catch

The Scanner class can raise a java.util.InputMismatchException if the user enters a non-float value. Let's handle this exception using a try-catch block.

Replace the code you added to the main method of FloatEquals.java with the following code:

import java.util.Scanner;

public class FloatEquals {
    public static void main(String[] args) {
        // Handling errors with try-catch
        try {
            Scanner sc = new Scanner(System.in);
            System.out.print("Enter value 1: ");
            Float num1 = sc.nextFloat();
            System.out.print("Enter value 2: ");
            Float num2 = sc.nextFloat();
            boolean equal = num1.equals(num2);
            System.out.println("Are the values equal? " + equal);
        } catch (java.util.InputMismatchException e) {
            System.out.println("Invalid input. Please enter a float value.");
        }
    }
}

Explanation: Here, we have added a try-catch block that surrounds the code that takes input from the user. If the user enters a value that is not a float, it raises an InputMismatchException which is handled by the catch block. It prints an error message to the console.

Compiling and running the program

Finally, we need to compile and run the program to see the output. In the terminal, navigate to the ~/project directory and execute the following command:

javac FloatEquals.java && java FloatEquals

Output:

Enter value 1: 12.5
Enter value 2: 12.5
Are the values equal? true

Testing invalid input

Let's test the try-catch block we implemented in Step 4. Enter a non-float value when prompted to enter the num1 value.

Output:

Enter value 1: abc
Invalid input. Please enter a float value.

Summary

In this lab, we have learned about the Float class equals() method in Java. We learned how to implement it, the syntax, and different examples of using it. We also learned how to handle errors using a try-catch block and tested our program for incorrect input.

Java Float Equals Method