在C++中，子类重载一个操作符时，如何调用父类被重载的操作符函数

使用static_cast运算符将子类转换为父类即可

 #include <iostream>

 using namespace std;

 class Base
 {
 public:
     Base(int p_n) : n(p_n) { }
     Base& operator=(const Base &base)
     {
         n = base.n;
         return *this;
     }

     friend ostream& operator<<(ostream &os, const Base &base)
     {
         os << "n: " << base.n;
         return os;
     }
 private:
     int n;
 };

 class Sub : public Base
 {
 public:
     Sub(int p_n, int p_m) : Base(p_n), m(p_m) { }
     Sub& operator=(const Sub &sub)
     {
         Base::operator=(static_cast<Base>(sub) );
         m = sub.m;
         return *this;
     }

     friend ostream& operator<<(ostream &os, const Sub &sub)
     {
         os << static_cast<Base>(sub) << ", ";
         os << "m: " << sub.m;
         return os;
     }
 private:
     int m;
 };

 int main()
 {
     Sub sub1(, );
     Sub sub2(-, -);

     cout << sub2 << endl;
     sub2 = sub1;
     cout << sub2 << endl;

     return ;
 }

运行结果：

n: -5, m: -6
n: 5, m: 6