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

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Base
 6 {
 7 public:
 8     Base(int p_n) : n(p_n) { }
 9     Base& operator=(const Base &base)
10     {
11         n = base.n;
12         return *this;
13     }
14 
15     friend ostream& operator<<(ostream &os, const Base &base)
16     {
17         os << "n: " << base.n;
18         return os;
19     }
20 private:
21     int n;
22 };
23 
24 class Sub : public Base
25 {
26 public:
27     Sub(int p_n, int p_m) : Base(p_n), m(p_m) { }
28     Sub& operator=(const Sub &sub)
29     {
30         Base::operator=(static_cast<Base>(sub) );
31         m = sub.m;
32         return *this;
33     }
34 
35     friend ostream& operator<<(ostream &os, const Sub &sub)
36     {
37         os << static_cast<Base>(sub) << ", ";
38         os << "m: " << sub.m;
39         return os;
40     }
41 private:
42     int m;
43 };
44 
45 int main()
46 {
47     Sub sub1(5, 6);
48     Sub sub2(-5, -6);
49 
50     cout << sub2 << endl;
51     sub2 = sub1;
52     cout << sub2 << endl;
53 
54     return 0;
55 }

运行结果：

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