c++ - C++ 中的结构

Question

我遇到了这段代码，但我无法理解这段代码的功能。 如果有人能解释一下，那将是一个很大的帮助。

struct A{
   int i,j;
   A(int ii,int jj) : i(ii),j(ii){}

   A(const A&a){
           }
   A& operator =(const A& a){
               i=a.i;j=a.j;
   }
};

int main()
{
int i;
A a(1,2);
A b(2,3);
A z = (a=b);
cout<<z.i<<" "<<z.j<<endl;

system("pause");
return 0;
}

Answer 1

解释:

struct A{
   int i,j;//members i and j

   A(int ii,int jj) : i(ii),j(ii){} //A constructor. Short form of A(int ii,int jj){i = ii;j = jj;} Original code is wrong too. Should be j(jj) instead of j(ii)

   A(const A&a){}//Another constructor. It is missing the assignment

   A& operator =(const A& a){
               i=a.i;j=a.j;
   }//Equal operator overload definition for A = another A. It copies the data from another A and assign to this new one
};

---

完整的工作代码:

#include <iostream>
using namespace std;

struct A{
   int i,j;

   A(int ii,int jj) : i(ii),j(jj){}

   A(const A&a){i=a.i;j=a.j;}

   A& operator =(const A& a){i=a.i;j=a.j;}
};

int main()
{
    int i;
    A a(1,2);
    A b(2,3);
    A z = (a=b);
    cout<<z.i<<" "<<z.j<<endl;

    return 0;
}