Introduction to Java Basics to Practical Applications: Frequently Asked Questions

Getting Started with Java: Create and run simple programs, and become familiar with the syntax and compilation process. Loops: Use a for loop to repeatedly execute a block of code. Array: Declare the array type, length, and fill elements. Method: Use classes to encapsulate code blocks and pass parameters to call methods. Exception handling: Use try-catch blocks to catch and handle exceptions. Practical application: Calculate and print the Fibonacci sequence using arrays and loops.

Java Basics to Practical Applications: Frequently Asked Questions

Question 1: How to get started with Java?

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, Java!");
    }
}

To get started with Java, create and run a simple program (like the example above) to become familiar with Java syntax and the compilation process.

Question 2: How to use loops?

for (int i = 0; i < 10; i++) {
    System.out.println(i);
}

This loop will print out all numbers from 0 to 9 (including 0). Use a for loop to repeatedly execute a block of code.

Question 3: How to use arrays?

int[] numbers = new int[5];
numbers[0] = 1;
numbers[1] = 2;

An array is a container that stores values ​​of the same type. To use an array, declare the array type, length, and padding elements.

Question 4: How to use the method?

public class MyClass {
    public static int sum(int a, int b) {
        return a + b;
    }
}

Methods are functions that encapsulate a block of code to perform a specific task. To use a method, call it by its name and pass the appropriate parameters.

Question 5: How to use exception handling?

try {
    // 可能引发异常的代码
} catch (Exception e) {
    // 处理异常
}

Exception handling is a mechanism for handling errors when a program is running. try-catch blocks allow you to catch exceptions and provide custom handling.

Practical case: Calculating the Fibonacci sequence

import java.util.Scanner;

public class Fibonacci {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter the number of terms: ");
        int n = input.nextInt();
        int[] fib = new int[n];

        // 初始化斐波那契数列
        fib[0] = 0;
        fib[1] = 1;

        // 计算斐波那契数列
        for (int i = 2; i < n; i++) {
            fib[i] = fib[i - 1] + fib[i - 2];
        }

        // 打印斐波那契数列
        for (int i : fib) {
            System.out.print(i + " ");
        }
        System.out.println();
    }
}

This program uses an array to store the Fibonacci sequence and uses a loop to calculate the value of each sequence item. , and print the final result.

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