使用指向類的指標時成員函式不起作用

場景：我有兩個類，每個類都包含一個指向另一個的指標（使用它們時，能夠參考另一個很重要，所以我認為這是合適的）。當我嘗試通過使用指向另一個類的指標和其中的 getter 函式從一個類訪問私有變數時，它可以完美運行。問題：使用 setter（在本例中為 addPoints）/操作變數但不會導致結果。

我是新手，所以這里的任何事情都可能是“不恰當的禮儀”和不好的做法。隨時指出他們！但也請嘗試提供解決方案。這也是我對SO的第一個問題，所以請溫柔！

相關代碼片段：

團隊.h

#include "Driver.h"

using namespace std;

class Team {
    int Points = 0;
    vector<Driver*> Drivers;
public:
    void addPoints(int gained); //does not work
    int getPoints(); //works perfectly
    Driver getDriver(int nr);
    void setInstance(vector<Driver*> drivers);
};

團隊.cpp

#include "Team.h"
#include "Driver.h"

using namespace std;

void Team::addPoints(int gained) {
    this->Points = this->Points   gained;
}
int Team::getPoints() {
    return this->Points;
}
Driver Team::getDriver(int nr) {
    return *Drivers[nr];
}
void Team::setInstance(vector<Driver*> drivers) {
    this->Drivers = drivers;
}

驅動程式.h

using namespace std;

class Team;
class Driver {
    int Points = 0;
    Team* DriversTeam;
public:
    void SetTeam(Team& team);
    Team getTeam();
    int getPoints(); //works
    void addPoints(int gained); //doesn't work
};

驅動程式.cpp

#include "Driver.h"
#include "Team.h"
using namespace std;

void Driver::SetTeam(::Team& team) {
    this->DriversTeam = &team;
}
Team Driver::getTeam() {
    return *DriversTeam;
}
int Driver::getPoints() {
    return this->Points;
}
void Driver::addPoints(int gained) {
    this->Points = this->Points   gained;
}

Initializer.cpp（將驅動程式鏈接到團隊）

void InitializeData(vector<Team>& teams, vector<Driver> &drivers) {
    //(...) 
    //reads each team in from data file to memory

    //key part:
    vector<Driver*> teamsDrivers;
    for (auto& iter : drivers) { //this loop mainly determines which driver to link with which teams
        if (iter.getName().compare(values[4]) == 0) { //values is csv line data in a string vector. I guess not the prettiest parsing method here but will be revised
            teamsDrivers.push_back(&iter);
        }else if(iter.getName().compare(values[5]) == 0) {
            teamsDrivers.push_back(&iter);
        }
    }

    tempTeam.setInstance(teamsDrivers);
    teams.push_back(tempTeam);

}

（將司機與團隊聯系起來）

//drivers are linked to teams last, as they are declared first (so I cannot link them to the yet nonexisting teams)
void LinkTeam(vector<Driver>& drivers, vector<Team>& teams) {
    for (auto& driverIter : drivers) { //iterate through drivers

        for (auto& teamIter : teams) { // iterate through teams
            bool found = 0;
            for (size_t i = 0; i < teamIter.DriverAmount(); i  ) {
                if (driverIter.getName() == teamIter.getDriver(i).getName()) {
                    driverIter.SetTeam(teamIter);
                    found = 1;
                    break;
                }
            }
            if (found) { //exit iterating if driver is found
                break;
            }
        }
    }
}

main.cpp 中的使用示例

teams[0].addPoints(10);
drivers[3].getTeam().addPoints(15); //driver 3 is linked to team 0

cout << teams[0].getPoints(); //15
cout << drivers[3].getTeam().getPoints(); //15


teams[0].getDriver(1).addPoints(20); //driver 1 of team 0=driver[3]
drivers[3].addPoints(25); 

cout << drivers[3].getPoints(); //25
cout << teams[0].getDriver(1).getPoints(); //25

我在這里先向您的幫助表示感謝。

uj5u.com熱心網友回復：

這很簡單：

您的getTeam()和getDriver()函式正在回傳物件的副本，而不是參考，因此它們addPoints()是在臨時副本上執行的，而不是真實的副本。

要修復它，只需將回傳型別更改為參考（添加&）：

Team& getTeam();

和

Driver& getDriver();

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