Complex a(3, 4);
Complex b(1, 2);
Complex c = a + b; // 希望能这样写

返回类型 operator@(参数列表) {
    // 实现逻辑
}

返回类型 operator@(const 类名& 左, const 类名& 右) {
    // 实现逻辑
}

class Complex {
private:
    double real, imag;
public:
    Complex(double r = 0, double i = 0) : real(r), imag(i) {}
<pre class='brush:php;toolbar:false;'>// 重载+，返回一个新的Complex对象
Complex operator+(const Complex& other) const {
    return Complex(real + other.real, imag + other.imag);
}

void print() const {
    cout << real << "+" << imag << "i" << endl;
}

};

// 使用示例： Complex a(3, 4); Complex b(1, 2); Complex c = a + b; c.print(); // 输出：4+6i

class Complex {
    // ... 同上
    friend ostream& operator<<(ostream& os, const Complex& c);
};
<p>ostream& operator<<(ostream& os, const Complex& c) {
os << c.real << "+" << c.imag << "i";
return os;
}</p><p>// 使用：
cout << a << " + " << b << " = " << c << endl;
// 输出：3+4i + 1+2i = 4+6i</p>

bool operator==(const Complex& other) const {
    return (real == other.real) && (imag == other.imag);
}
<p>bool operator!=(const Complex& other) const {
return !(*this == other); // 复用==的结果
}</p>

class String {
private:
    char* data;
public:
    String(const char* str = nullptr) {
        if (str) {
            data = new char[strlen(str)+1];
            strcpy(data, str);
        } else {
            data = new char[1];
            data[0] = '\0';
        }
    }
<pre class='brush:php;toolbar:false;'>// 赋值运算符重载
String& operator=(const String& other) {
    if (this == &other) return *this; // 自赋值检查

    delete[] data; // 释放原有内存
    data = new char[strlen(other.data) + 1];
    strcpy(data, other.data);
    return *this;
}

~String() { delete[] data; }

};

class MyArray {
private:
    int arr[10];
public:
    int& operator[](int index) {
        return arr[index]; // 返回引用，支持修改
    }
<pre class='brush:php;toolbar:false;'>const int& operator[](int index) const {
    return arr[index]; // const版本，用于只读访问
}

};

// 使用： MyArray a; a[0] = 100; // 调用非const版本 cout