Adding Two Numbers in Java: Simple Examples and Methods

回答：

Certainly! In Java, adding two numbers can be accomplished in various ways, depending on the context (e.g., user input, hardcoded values, etc.). Below, I'll provide a simple introduction to adding two numbers in Java, along with examples.

Introduction to Adding Two Numbers in Java

Java is a versatile programming language that allows you to perform arithmetic operations easily. To add two numbers, you typically follow these steps:

Declare Variables: Create variables to hold the numbers you want to add.
Perform Addition: Use the + operator to add the numbers.
Display the Result: Print the result to the console.

Example 1: Adding Two Hardcoded Numbers

Here’s a simple example where we add two hardcoded numbers:

public class AddTwoNumbers {
    public static void main(String[] args) {
        // Declare two numbers
        int number1 = 10;
        int number2 = 20;

        // Add the two numbers
        int sum = number1 + number2;

        // Display the result
        System.out.println("The sum of " + number1 + " and " + number2 + " is: " + sum);
    }
}

Output:

The sum of 10 and 20 is: 30

Example 2: Adding Two Numbers from User Input

In this example, we will take input from the user to add two numbers:

import java.util.Scanner;

public class AddTwoNumbers {
    public static void main(String[] args) {
        // Create a Scanner object for user input
        Scanner scanner = new Scanner(System.in);

        // Prompt the user to enter two numbers
        System.out.print("Enter the first number: ");
        int number1 = scanner.nextInt();

        System.out.print("Enter the second number: ");
        int number2 = scanner.nextInt();

        // Add the two numbers
        int sum = number1 + number2;

        // Display the result
        System.out.println("The sum of " + number1 + " and " + number2 + " is: " + sum);

        // Close the scanner
        scanner.close();
    }
}

Output Example:

Enter the first number: 15
Enter the second number: 25
The sum of 15 and 25 is: 40

Example 3: Adding Two Floating-Point Numbers

You can also add floating-point numbers (decimals) in Java. Here’s how:

public class AddTwoNumbers {
    public static void main(String[] args) {
        // Declare two floating-point numbers
        double number1 = 10.5;
        double number2 = 20.3;

        // Add the two numbers
        double sum = number1 + number2;

        // Display the result
        System.out.println("The sum of " + number1 + " and " + number2 + " is: " + sum);
    }
}