主函数中的 C++ 私有变量访问

Question

#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;

class Movie{
    string title;
    string genre;
    int rating;
public:
    Movie(string t, string g);
    void printDetail();
};

Movie :: Movie(string t, string g){
    title = t;
    genre = g;
    rating = rand()%10;      
}

void Movie :: printDetail(){
    cout <<" Title  : " <<title<<endl;
    cout <<"    Genre  : " <<genre<<endl;
    cout <<"    Rating : " <<rating<<endl;
}

在 main 我有以下内容：

int main()
{
   Movie M[5]={
        Movie("The Avengers","Action"),
        Movie("Infinity War","Action"),
        Movie("Gupigain Baghabain","Comedy"),
        Movie("Anonymous 616","Horror"),
        Movie("Sara's Notebook","Thriller")
        };

        for(int i=0;i<5;i++){
            cout <<" "<<i+1<<".";
            M[i].printDetail();
            cout<<endl;
        }

        M[0].rating; // Here i need to access to rating...!!

       // Here I need to compare which movies rating is highest..!! 
       // So I need to access rating variable...!! 
       // But how can I do this...!! 
       // There has a condition... That is I can't declare any other member function..!!!
}

在这里我要显示哪个评分最高哪个评分最低..!!

Answer 1

将此添加到 class:

bool isHighest(Movie otherMovie){
return rating > otherMovie.rating;
}

如果需要，可以将其设为运算符：

bool operator >(Movie otherMovie){
return rating > otherMovie.rating;
}

Answer 2

您可以使 getter 和 setter 函数间接访问私有成员还有另一个不标准的 hack：将私有成员的 offest 获取到 class 头部，然后获取 class 的地址并将 offest 添加到它，因此您拥有私有地址会员，可以直接访问这不受标准 c++ 支持，您需要自己进行计算，在您的情况下并不困难当您想从 dll 中获取结构或 class 以获取特定成员的值并且您没有结构的定义但您可以使用从 dll 中获取 rva offest 时，可以使用此方法各种方法，如反汇编 dll 的某些字节

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