全面的程式語言代碼參考

深入了解多種程式語言的實用範例與應用

關鍵要點

多樣化的程式語言範例涵蓋基礎與進階應用
每種語言均提供實用的「Hello, World!」及功能性程式碼
豐富的學習資源與參考鏈接助您深入掌握

程式語言概覽

在現代軟體開發中，掌握多種程式語言是提升技能的重要途徑。以下將介紹十種常見程式語言的基本範例，涵蓋從簡單輸出到函數定義、條件判斷、迴圈結構等多方面應用。

Python

基本範例

# Hello, World!
print("Hello, World!")

變數與輸出

name = "Tom"
age = 25
print(f"Hello, {name}! You are {age} years old.")

條件判斷

if age >= 18:
    print("You are an adult")
else:
    print("You are a minor")

迴圈

for i in range(5):
    print(i)

函數定義

def greet(name):
    return f"Hello, {name}!"
    
print(greet("Alice"))

JavaScript

基本範例

// Hello, World!
console.log("Hello, World!");

變數宣告

let name = "Tom";
const age = 25;

函數定義

function greet(name) {
    return `Hello, ${name}!`;
}

console.log(greet("Bob"));

陣列操作

let numbers = [1, 2, 3, 4, 5];
numbers.forEach(num => {
    console.log(num);
});

物件操作

let person = {
    name: "Tom",
    age: 25,
    sayHello() {
        console.log(`Hello, I'm ${this.name}`);
    }
};

person.sayHello();

Java

基本範例

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

變數與資料型態

String name = "Tom";
int age = 25;
System.out.println("Hello, " + name + "! You are " + age + " years old.");

條件判斷

if (age >= 18) {
    System.out.println("You are an adult");
} else {
    System.out.println("You are a minor");
}

迴圈

for (int i = 0; i < 5; i++) {
    System.out.println(i);
}

函數定義

public class Calculator {
    public static void main(String[] args) {
        int result = addNumbers(5, 3);
        System.out.println("兩數相加的結果是: " + result);
    }

    public static int addNumbers(int a, int b) {
        return a + b;
    }
}

C++

基本範例

// Hello, World!
#include <iostream>
using namespace std;

int main() {
    cout << "Hello, World!" << endl;
    return 0;
}

變數宣告與輸出

string name = "Tom";
int age = 25;
cout << "Hello, " << name << "! You are " << age << " years old." << endl;

條件判斷

if (age >= 18) {
    cout << "You are an adult" << endl;
} else {
    cout << "You are a minor" << endl;
}

迴圈

for(int i = 0; i < 5; i++) {
    cout << i << " ";
}

函數定義

int addNumbers(int a, int b) {
    return a + b;
}

int main() {
    int result = addNumbers(5, 3);
    cout << "兩數相加的結果是: " << result << endl;
    return 0;
}

資料結構

int numbers[5] = {1, 2, 3, 4, 5};
for(int i = 0; i < 5; i++) {
    cout << numbers[i] << " ";
}

C#

基本範例

// Hello, World!
using System;

class Program {
    static void Main() {
        Console.WriteLine("Hello, World!");
    }
}

變數宣告與輸出

string name = "Tom";
int age = 25;
Console.WriteLine($"Hello, {name}! You are {age} years old.");

條件判斷

if (age >= 18) {
    Console.WriteLine("You are an adult");
} else {
    Console.WriteLine("You are a minor");
}

迴圈

for(int i = 0; i < 5; i++) {
    Console.WriteLine(i);
}

函數定義

static int AddNumbers(int a, int b) {
    return a + b;
}

static void Main() {
    int result = AddNumbers(5, 3);
    Console.WriteLine($"兩數相加的結果是: {result}");
}

Go

基本範例

// Hello, World!
package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}

變數宣告與輸出

package main

import "fmt"

func main() {
    name := "Tom"
    age := 25
    fmt.Printf("Hello, %s! You are %d years old.\n", name, age)
}

條件判斷

if age >= 18 {
    fmt.Println("You are an adult")
} else {
    fmt.Println("You are a minor")
}

迴圈

for i := 0; i < 5; i++ {
    fmt.Println(i)
}

函數定義

func greet(name string) string {
    return fmt.Sprintf("Hello, %s!", name)
}

func main() {
    fmt.Println(greet("Alice"))
}

Ruby

基本範例

# Hello, World!
puts "Hello, World!"

變數宣告與輸出

name = "Tom"
age = 25
puts "Hello, #{name}! You are #{age} years old."

條件判斷

if age >= 18
  puts "You are an adult"
else
  puts "You are a minor"
end

迴圈

5.times do |i|
  puts i
end

函數定義

def greet(name)
  "Hello, #{name}!"
end

puts greet("Alice")

Rust

基本範例

// Hello, World!
fn main() {
    println!("Hello, World!");
}

變數宣告與輸出

fn main() {
    let name = "Tom";
    let age = 25;
    println!("Hello, {}! You are {} years old.", name, age);
}

條件判斷

fn main() {
    let age = 25;
    if age >= 18 {
        println!("You are an adult");
    } else {
        println!("You are a minor");
    }
}

迴圈

fn main() {
    for i in 0..5 {
        println!("{}", i);
    }
}

函數定義

fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

fn main() {
    println!("{}", greet("Alice"));
}

Swift

基本範例

// Hello, World!
import Swift

print("Hello, World!")

變數宣告與輸出

let name = "Tom"
let age = 25
print("Hello, \(name)! You are \(age) years old.")

條件判斷

if age >= 18 {
    print("You are an adult")
} else {
    print("You are a minor")
}

迴圈

for i in 0..<5 {
    print(i)
}

函數定義

func greet(name: String) -> String {
    return "Hello, \(name)!"
}

print(greet(name: "Alice"))

Kotlin

基本範例

// Hello, World!
fun main() {
    println("Hello, World!")
}

變數宣告與輸出

fun main() {
    val name = "Tom"
    val age = 25
    println("Hello, $name! You are $age years old.")
}

條件判斷

fun main() {
    val age = 25
    if (age >= 18) {
        println("You are an adult")
    } else {
        println("You are a minor")
    }
}

迴圈

fun main() {
    for (i in 0 until 5) {
        println(i)
    }
}

函數定義

fun greet(name: String): String {
    return "Hello, $name!"
}

fun main() {
    println(greet("Alice"))
}

功能比較表

功能/語言	Python	JavaScript	Java	C++	C#	Go	Ruby	Rust	Swift	Kotlin
語法簡潔性	高	中	中	中	中	高	高	中	高	高
主要應用領域	數據分析、AI、網頁開發	前端、後端開發	企業應用、Android開發	系統程式、遊戲開發	Windows應用、遊戲開發	高效能應用、網路服務	網頁開發、腳本編寫	系統程式、嵌入式系統	iOS、macOS應用	Android開發、跨平台應用
學習曲線	平緩	平緩	陡峭	陡峭	中等	中等	平緩	中等	平緩	平緩
社群支援	廣泛	廣泛	廣泛	廣泛	廣泛	成長中	活躍	活躍	成長中	快速增長

進階應用示例

除了基本的語法和結構，進階應用能夠展示各種語言在實際開發中的強大功能。以下將提供一些進階範例，如資料庫連接、網路應用、物件導向設計等。

資料庫連接

Python 與 SQLite

import sqlite3

# 連接到 SQLite 資料庫
conn = sqlite3.connect('example.db')
c = conn.cursor()

# 創建表
c.execute('''CREATE TABLE IF NOT EXISTS users
             (id INTEGER PRIMARY KEY, name TEXT, age INTEGER)''')

# 插入資料
c.execute("INSERT INTO users (name, age) VALUES (?, ?)", ("Alice", 30))

# 確認修改
conn.commit()

# 查詢資料
c.execute("SELECT * FROM users")
print(c.fetchall())

# 關閉連接
conn.close()

JavaScript 與 Node.js 連接 MongoDB

// 安裝必要套件: npm install mongodb

const { MongoClient } = require('mongodb');
const uri = "mongodb://localhost:27017";
const client = new MongoClient(uri);

async function run() {
    try {
        await client.connect();
        const database = client.db('testdb');
        const collection = database.collection('users');
        
        // 插入文件
        const doc = { name: "Bob", age: 25 };
        const result = await collection.insertOne(doc);
        console.log(`A document was inserted with the _id: ${result.insertedId}`);
        
        // 查詢文件
        const users = await collection.find().toArray();
        console.log(users);
    } finally {
        await client.close();
    }
}

run().catch(console.dir);

Java 與 MySQL 連接

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class MySQLExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/testdb";
        String user = "root";
        String password = "password";

        try {
            Connection conn = DriverManager.getConnection(url, user, password);
            Statement stmt = conn.createStatement();

            // 創建表
            String sql = "CREATE TABLE IF NOT EXISTS users (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), age INT)";
            stmt.executeUpdate(sql);

            // 插入資料
            sql = "INSERT INTO users (name, age) VALUES ('Charlie', 28)";
            stmt.executeUpdate(sql);

            // 查詢資料
            sql = "SELECT * FROM users";
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()) {
                System.out.println("ID: " + rs.getInt("id") + 
                                   ", Name: " + rs.getString("name") + 
                                   ", Age: " + rs.getInt("age"));
            }

            conn.close();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

物件導向設計

C++ 的物件導向範例

#include <iostream>
#include <string>
using namespace std;

class Person {
private:
    string name;
    int age;

public:
    Person(string n, int a) : name(n), age(a) {}
    
    void introduce() {
        cout << "Hello, I'm " << name << " and I'm " << age << " years old." << endl;
    }
};

int main() {
    Person p("Dave", 40);
    p.introduce();
    return 0;
}

Java 的物件導向範例

public class Person {
    private String name;
    private int age;
    
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    
    public void introduce() {
        System.out.println("Hello, I'm " + name + " and I'm " + age + " years old.");
    }
    
    public static void main(String[] args) {
        Person p = new Person("Eve", 35);
        p.introduce();
    }
}