Introduction to Java Basics to Practical Applications: Practical Experience Sharing

Java programming includes basic knowledge and practical applications. Fundamentals include variables and data types, control flow, arrays and collections, object-oriented programming, and exception handling. Practical examples include calculating BMI and building a student management system.

Java Basics to Practical Application: Practical Experience Sharing

Introduction

Java is a powerful programming language that is widely used in various practical scenarios. As a beginner, it is crucial to understand the basics of Java and master its practical applications.

Basic knowledge

• Variables and data types
• Control process (if, for, switch, etc.)
• Arrays and collections
• Object-oriented programming (categories, objects, inheritance, polymorphism)
• Exception handling

Practical examples

Case 1: Calculate BMI index

import java.util.Scanner;

public class BMICalculator {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        // 取得使用者輸入的身高和體重
        System.out.print("請輸入您的身高 (公尺)：");
        double height = input.nextDouble();

        System.out.print("請輸入您的體重 (公斤)：");
        double weight = input.nextDouble();

        // 計算 BMI 指數
        double bmi = weight / (height * height);

        // 顯示結果
        System.out.printf("您的 BMI 指數：%.2f\n", bmi);
    }
}

Case 2: Establish a student management system

import java.util.ArrayList;
import java.util.List;

public class StudentManagementSystem {

    private List<Student> students;

    public StudentManagementSystem() {
        students = new ArrayList<>();
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public List<Student> getAllStudents() {
        return students;
    }

    public Student getStudentById(int id) {
        for (Student student : students) {
            if (student.getId() == id) {
                return student;
            }
        }
        return null;
    }

    public void removeStudentById(int id) {
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId() == id) {
                students.remove(i);
                return;
            }
        }
    }

    // 其他方法...
}

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