C ++通用運算符重載

Question

如何使用運算符重載來添加兩個對象而又不使其成為任何對象的成員？ 這與插入運算符重載有關嗎？

所以代替這個，使用更通用的東西，即與任何對象一起使用？：

sameObjectType operator + ( const sameObjectType  &x,  const sameObjectType &y ) {
    sameObjectType z;
    z = x+y;

    return z;
}

// I want to do the same for subtraction operatoR

sameObjectType operator - ( const sameObjectType  &x,  const sameObjectType &y ) {
    sameObjectType z;
    z = x-y;

    return z;
}

Answer 1

您可以從此示例代碼中獲得想法。

#include <iostream>
class One {
private:
 int num1, num2;

public:
  One(int num1, int num2) : num1(num1), num2(num2) {}
  One& operator += (const One&);
  friend bool operator==(const One&, const One&);
  friend std::ostream& operator<<(std::ostream&, const One&);
};

std::ostream&
 operator<<(std::ostream& os, const One& rhs) {
   return os << "(" << rhs.num1 << "@" << rhs.num2 << ")";
 }

One& One::operator+=(const One& rhs) {
  num1 += rhs.num1;
  num2 += rhs.num2;
  return *this;
}

One operator+(One lhs, const One &rhs)
{
 return lhs+=rhs;
}

 int main () {
 One x(1,2), z(3,4);
 std::cout << x << " + " << z << " => " << (x+z) << "\n";
 }