在C++中，可以通過定義成員函數或非成員函數來實現運算符重載。以下是一些示例代碼：

1. 重載加法運算符：

class Complex {
private:
    double real;
    double imaginary;
public:
    Complex(double r, double i) : real(r), imaginary(i) {}

    Complex operator+(const Complex& other) {
        return Complex(real + other.real, imaginary + other.imaginary);
    }
};

int main() {
    Complex c1(1, 2);
    Complex c2(3, 4);
    Complex result = c1 + c2;
    return 0;
}

2. 重載自增運算符：

class Number {
private:
    int value;
public:
    Number(int v) : value(v) {}

    Number& operator++() {
        value++;
        return *this;
    }
};

int main() {
    Number num(5);
    ++num;
    return 0;
}

3. 重載流插入運算符：

#include <iostream>

class Complex {
private:
    double real;
    double imaginary;
public:
    Complex(double r, double i) : real(r), imaginary(i) {}

    friend std::ostream& operator<<(std::ostream& os, const Complex& c) {
        os << c.real << " + " << c.imaginary << "i";
        return os;
    }
};

int main() {
    Complex c(1, 2);
    std::cout << c << std::endl;
    return 0;
}

需要注意的是，運算符重載一般應該符合運算符的原有語義，遵循常規的運算符規則，并不應該引入令人困惑的行為。