Question

我用新的“game_struct”声明了一个结构。它有以下内容：

struct game_struct{

scene scene_container[10]; 

player cPlayer;;

scene scene_one;

this->scene_container[0] = scene_one; 
this->scene_container[0].image = " "; 
this->scene_container[0].scene_message = "Welcome to the home screen of the game."; 


};

它给出错误“此''之前的预期不合格ID”。我一直试图解决它，但我无法弄明白。任何建议将不胜感激。

Answer 1

this->scene_container[0] = scene_one; 
this->scene_container[0].image = " "; 
this->scene_container[0].scene_message = "Welcome to the home screen of the game.";

您不能在this

的功能之外使用game_struct

你想做的可能是：

struct game_struct{

scene scene_container[10]; 

player cPlayer;

scene scene_one;

game_struct(){
   this->scene_container[0] = scene_one; 
   this->scene_container[0].image = " "; 
   this->scene_container[0].scene_message = "Welcome to the home screen of the game."; 
}


};

Answer 2

上述解决方案scene_container[0]和scene_one不会引用相同的场景。 scene_container只是从scene_one分配的副本，这是毫无意义的，因为它们都是在构造game_struct时默认构建的。这要好得多：

struct game_struct {

        scene scene_container[10];

    player cPlayer;

    scene* scene_one;

    game_struct() {
        scene_one = scene_container; // points to first element
        scene_one->image = " ";
        scene_one->scene_message =
                "Welcome to the home screen of the game.";
    }

};

编辑：我希望我不必拼出来。但似乎这是我的第一个否定，我想我必须：

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

struct scene {
    string image;
    string scene_message;
};
struct player {};

struct game_struct {

    scene scene_container[10];

    player cPlayer;

    scene scene_one;

    game_struct() /* all members are default constructed PRIOR TO ENTERING constructor block */
    {
        this->scene_container[0] = scene_one; /* this is not copy constructing, this is
            COPY ASSIGNING two identically constructed
            scene objects. All it does it non static member
            copy assignment for every member of scene_container[0] */
        this->scene_container[0].image = " ";
        this->scene_container[0].scene_message =
                "Welcome to the home screen of the game.";
    }
};

int main(int argc, char** argv) {
    game_struct gs;
    cout << "scene_one.scene_message : " << gs.scene_one.scene_message << endl;
    cout << "scene_container[0].scene_message : " << gs.scene_container[0].scene_message << endl;
}

这不足为奇：

scene_one.scene_message : 
scene_container[0].scene_message : Welcome to the home screen of the game.

这个结构声明有什么问题？

2 个答案: