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📌 12 门语言基础语法跨语言对照大屏 ​

本页面对比 Java, JS, Python, C++, Rust, Go, PHP, C#, Ruby, Kotlin 十门编程语言，并将 HTML 与 CSS 作为两门声明式 Web 语言独立说明。HTML/CSS 不具备通用函数、循环或类模型，不应强行套入命令式语法骨架。

1.1 变量声明与常量 (Variables & Constants) ​

☕ Java ​

java
// Java: final 关键字声明不可变常量
final String lang = "Java";

🟨 JavaScript ​

javascript
// JavaScript: const 声明不可变常量，let 声明可变变量
const lang = "JavaScript";

🐍 Python ​

python
# Python: 大写约定表示常量，使用类型注解
LANG: str = "Python"

⚡ C++ ​

cpp
// C++: const 关键字声明常量
const std::string lang = "C++";

🦀 Rust ​

rust
// Rust: let 默认不可变，常量使用 const
let lang: &str = "Rust";

🐹 Go ​

go
// Go: const 关键字声明常量，:= 自动推导变量
const lang = "Go"

🐘 PHP ​

php
// PHP: define() 或 const 声明常量
define("LANG", "PHP");

🔷 C# ​

csharp
// C#: const 关键字声明编译期常量
const string lang = "C#";

💎 Ruby ​

ruby
# Ruby: 首字母大写标识常量
LANG = "Ruby"

🟣 Kotlin ​

kotlin
// Kotlin: val 声明不可变变量，var 声明可变变量
val lang: String = "Kotlin"

1.2 基本数据类型 (Basic Data Types) ​

☕ Java ​

java
int age = 25;
double salary = 8500.50;
boolean isActive = true;
String name = "Java";

🟨 JavaScript ​

javascript
let age = 25;
const salary = 8500.50;
const isActive = true;
const name = "JavaScript";

🐍 Python ​

python
age: int = 25
salary: float = 8500.50
is_active: bool = True
name: str = "Python"

⚡ C++ ​

cpp
int age = 25;
double salary = 8500.50;
bool isActive = true;
std::string name = "C++";

🦀 Rust ​

rust
let age: u32 = 25;
let salary: f64 = 8500.50;
let is_active: bool = true;
let name: &str = "Rust";

🐹 Go ​

go
age := 25
salary := 8500.50
isActive := true
name := "Go"

🐘 PHP ​

php
$age = 25;
$salary = 8500.50;
$isActive = true;
$name = "PHP";

🔷 C# ​

csharp
int age = 25;
double salary = 8500.50;
bool isActive = true;
string name = "C#";

💎 Ruby ​

ruby
age = 25
salary = 8500.50
is_active = true
name = "Ruby"

🟣 Kotlin ​

kotlin
val age: Int = 25
val salary: Double = 8500.50
val isActive: Boolean = true
val name: String = "Kotlin"

2.1 条件分支与控制流 (Control Flow if/else) ​

☕ Java ​

java
if (isActive) {
    System.out.println("Status: Active Worker");
} else {
    System.out.println("Status: Inactive Worker");
}

🟨 JavaScript ​

javascript
if (isActive) {
    console.log("Status: Active Worker");
} else {
    console.log("Status: Inactive Worker");
}

🐍 Python ​

python
if is_active:
    print("Status: Active Worker")
else:
    print("Status: Inactive Worker")

⚡ C++ ​

cpp
if (isActive) {
    std::cout << "Status: Active Worker" << std::endl;
} else {
    std::cout << "Status: Inactive Worker" << std::endl;
}

🦀 Rust ​

rust
if is_active {
    println!("Status: Active Worker");
} else {
    println!("Status: Inactive Worker");
}

🐹 Go ​

go
if isActive {
    fmt.Println("Status: Active Worker")
} else {
    fmt.Println("Status: Inactive Worker")
}

🐘 PHP ​

php
if ($isActive) {
    echo "Status: Active Worker\n";
} else {
    echo "Status: Inactive Worker\n";
}

🔷 C# ​

csharp
if (isActive) {
    Console.WriteLine("Status: Active Worker");
} else {
    Console.WriteLine("Status: Inactive Worker");
}

💎 Ruby ​

ruby
if is_active
  puts "Status: Active Worker"
else
  puts "Status: Inactive Worker"
end

🟣 Kotlin ​

kotlin
if (isActive) {
    println("Status: Active Worker")
} else {
    println("Status: Inactive Worker")
}

2.2 集合与循环遍历 (Collections & Loops) ​

☕ Java ​

java
List<String> skills = Arrays.asList("OOP", "Concurrency", "JVM");
for (String skill : skills) {
    System.out.print(skill + " ");
}

🟨 JavaScript ​

javascript
const skills = ["V8 Engine", "Async/Await", "ES6+"];
console.log("Skills:", skills.join(" "));

🐍 Python ​

python
skills: list[str] = ["Dynamic Typing", "List Comprehension", "GIL"]
print("Skills:", " ".join(skills))

⚡ C++ ​

cpp
std::vector<std::string> skills = {"RAII", "Pointers", "Templates"};
for (const auto& skill : skills) {
    std::cout << skill << " ";
}

🦀 Rust ​

rust
let skills: Vec<&str> = vec!["Ownership", "Borrow Checker", "Cargo"];
println!("Skills: {}", skills.join(" "));

🐹 Go ​

go
skills := []string{"Goroutines", "Channels", "Interfaces"}
fmt.Printf("Skills: %s\n", strings.Join(skills, " "))

🐘 PHP ​

php
$skills = ["Composer", "Laravel", "OpCache"];
echo "Skills: " . implode(" ", $skills) . "\n";

🔷 C# ​

csharp
var skills = new List<string> { "LINQ", "ASP.NET Core", "Entity Framework" };
Console.WriteLine("Skills: " + string.Join(" ", skills));

💎 Ruby ​

ruby
skills = ["Rails", "Blocks", "Metaprogramming"]
puts "Skills: #{skills.join(' ')}"

🟣 Kotlin ​

kotlin
val skills = listOf("Coroutines", "Null Safety", "Extension Functions")
println("Skills: ${skills.joinToString(" ")}")

3.1 函数定义与默认参数 (Functions) ​

☕ Java ​

java
public static double calculateBonus(double base, double ratio) {
    return base * ratio;
}

🟨 JavaScript ​

javascript
function calculateBonus(base, ratio = 0.1) {
    return base * ratio;
}

🐍 Python ​

python
def calculate_bonus(base: float, ratio: float = 0.1) -> float:
    return base * ratio

⚡ C++ ​

cpp
double calculateBonus(double base, double ratio = 0.1) {
    return base * ratio;
}

🦀 Rust ​

rust
fn calculate_bonus(base: f64, ratio: f64) -> f64 {
    base * ratio
}

🐹 Go ​

go
func calculateBonus(base float64, ratio float64) float64 {
    return base * ratio
}

🐘 PHP ​

php
function calculateBonus(float $base, float $ratio = 0.1): float {
    return $base * $ratio;
}

🔷 C# ​

csharp
public static double CalculateBonus(double baseVal, double ratio = 0.1) {
    return baseVal * ratio;
}

💎 Ruby ​

ruby
def calculate_bonus(base, ratio = 0.1)
  base * ratio
end

🟣 Kotlin ​

kotlin
fun calculateBonus(base: Double, ratio: Double = 0.1): Double = base * ratio

4.1 结构化数据/类与构造器 (Class / Struct) ​

☕ Java ​

java
class Person {
    private String name; private int age;
    public Person(String name, int age) { this.name = name; this.age = age; }
    public String getInfo() { return name + " (" + age + " years old)"; }
}

🟨 JavaScript ​

javascript
class Person {
    constructor(name, age) { this.name = name; this.age = age; }
    getInfo() { return `${this.name} (${this.age} years old)`; }
}

🐍 Python ​

python
class Person:
    def __init__(self, name: str, age: int) -> None:
        self.name = name
        self.age = age
    def get_info(self) -> str:
        return f"{self.name} ({self.age} years old)"

⚡ C++ ​

cpp
class Person {
private:
    std::string name; int age;
public:
    Person(std::string n, int a) : name(n), age(a) {}
    std::string getInfo() const { return name + " (" + std::to_string(age) + " years old)"; }
};

🦀 Rust ​

rust
struct Person { name: String, age: u32 }
impl Person {
    fn new(name: &str, age: u32) -> Self { Person { name: name.to_string(), age } }
    fn get_info(&self) -> String { format!("{} ({} years old)", self.name, self.age) }
}

🐹 Go ​

go
type Person struct { Name string; Age int }
func (p Person) GetInfo() string {
    return fmt.Sprintf("%s (%d years old)", p.Name, p.Age)
}

🐘 PHP ​

php
class Person {
    public function __construct(public string $name, public int $age) {}
    public function getInfo(): string { return "{$this->name} ({$this->age} years old)"; }
}

🔷 C# ​

csharp
public class Person
{
    public string Name { get; } public int Age { get; }
    public Person(string name, int age) { Name = name; Age = age; }
    public string GetInfo() => $"{Name} ({Age} years old)";
}

💎 Ruby ​

ruby
class Person
  attr_reader :name, :age
  def initialize(name, age)
    @name = name; @age = age
  end
  def get_info
    "#{@name} (#{@age} years old)"
  end
end

🟣 Kotlin ​

kotlin
class Person(val name: String, val age: Int) {
    fun getInfo(): String = "$name ($age years old)"
}

5. HTML 与 CSS 的声明式语法模型 ​

编程语言概念HTML 对应模型CSS 对应模型
变量与数据元素、属性、文本与 DOM 状态自定义属性、属性值与计算值
条件与循环无通用控制流；由文档结构和浏览器行为表达媒体查询、容器查询等条件规则；无通用循环
函数无通用函数calc()、min()、color-mix() 等值函数
类class 是元素分类属性，不是面向对象的类类选择器匹配具有相应 class 属性的元素

🟧 HTML：结构与语义 ​

html
<article class="card">
  <h2>HTML 描述内容角色</h2>
  <p>元素和属性共同构成浏览器可解析的文档树。</p>
</article>

🟦 CSS：选择器与声明 ​

css
:root { --accent: #4f46e5; }

.card {
  display: grid;
  gap: 1rem;
  border-color: var(--accent);
}

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