c++ - 运营商_surrogate_func : no matching overload found and 2 other errors

Question

我编写了一段代码，它创建了一个总线列表，您可以修改和管理这些总线。整个管理过程是通过在控制台中写入字符串来进行的。运行代码后，我收到 3 个错误，据我所知，没有一个可以修复。代码是这样规划的:

NEW_BUS - 通过获取公交车的编号、停靠站数量和停靠站列表在列表中添加新公交车。ALL_BUSES - 按字典顺序显示所有总线(按名称)STOPS_FOR_BUS - 显示特定公交车之后的所有站点。BUSES_FOR_STOP - 显示所有经过特定站点的公交车。

错误列表如下:1. operator _surrogate_func: 找不到匹配的重载2. 无法特化函数模板 'unknown-type std::less::operator ()(_Ty 1 &&,_Ty2 &&)3. 非法表达

所有错误都来自 xutility 文件的第 617 行。

   #include <iostream>
   #include <string>
   #include <vector>
   #include <list>
   #include <tuple>
   #include <iterator>

   using namespace std;

   class Bus {
   public:
    int StopsAmount;
    string BusNumber;
    vector<string> Stops;

    Bus(tuple<string, int, vector<string>> BusParams) {
        BusNumber = get<0>(BusParams);
        StopsAmount = get<1>(BusParams);
        Stops = get<2>(BusParams);
    }

    void ShowStops() {
        cout << BusNumber << ": ";
        for (int i = 0; i < StopsAmount; i++) cout << Stops[i] << " ";
        cout << "\n";
    }

    bool FindStop(string Stop) {
        for (int i = 0; i < StopsAmount; i++) {
            if (Stops[i] == Stop) {
                return true;
            }
        }
        return false;
            }
         };   

      class BusTraffic {
      public:
        BusTraffic() {
            while (true) {
                string Request;
                cin >> Request;
                switch (Request[0]) {
                case 'N': NEW_BUS(Request.substr(8, Request.length() - 8))      ;
                break;
            case 'B': BUSES_FOR_STOP(Request.substr(15, Request.length() - 15));
                break;
            case 'S': STOPS_FOR_BUS(Request.substr(14, Request.length() - 14));
                break;
            case 'A': ALL_BUSES();
                break;
            }
        }
    }

      private:
        list<Bus> BusList;

    void NEW_BUS(string Request) {
        BusList.push_back(Bus::Bus(SplitString(Request)));
    }

    void BUSES_FOR_STOP(string Stop) {
        cout << Stop << ": ";
        for (list<Bus>::iterator It = BusList.begin(); It != BusList.end(); It++) {
            if (It->FindStop(Stop)) {
                cout << It->BusNumber << " ";
            }
        }
        cout << endl;
    }

    void STOPS_FOR_BUS(string Name) {
        cout << Name << ": ";
        for (list<Bus>::iterator It = BusList.begin(); It != BusList.end(); It++) {
            if (It->BusNumber == Name) {
                It->ShowStops();
            }
        }
    }

    void ALL_BUSES() {
        if (BusList.size() > 0) {
            BusList.sort();
            for (list<Bus>::iterator It = BusList.begin(); It != BusList.end(); It++) {
                cout << It->BusNumber << ": ";
                It->ShowStops();
            }
        }
        else {
            cout << "No buses" << endl;
        }
    }

    // Converting string to information about bus
    tuple<string, int, vector<string>> &SplitString(string str) {
        tuple<string, int, vector<string>> BusParams;
        string Word = "";
        int WordNum = 0;

        for (auto Letter : str) {
            if (Letter == ' ') {
                if (WordNum == 0) get<0>(BusParams) = Word; 
                if (WordNum == 1) get<1>(BusParams) = stoi(Word);
                if (WordNum == 2) get<2>(BusParams).push_back(Word);
                Word = "";
                WordNum++;
            }
            else {
                Word = Word + Letter;
            }
        }
        get<2>(BusParams).push_back(Word);
        return BusParams;
        }
      };

      int main() {
        BusTraffic TestTraffic;
        return 0;
      }

Answer 1

不幸的是，你是绝对正确的。这里的错误信息太糟糕了。您只是从经验中学会将其解释为缺失的小于运算符。

所以一些事情是这样的:

bool operator< (const Bus& lhs, const Bus& rhs) {
  // however you want to sort them...
   return (lhs.BusNumber < rhs.BusNumber);
}

另一个小错误在 NEW_BUS 中:在 C++ 中，您不需要指定构造函数名称。所以它不是 Bus::Bus 它只是 Bus

最后但同样重要的是，您的 SplitString 正在返回对局部变量的引用。一般来说，这是一个坏主意，因为当您尝试时，内存可能根本无法再访问。只需从返回类型中删除“&”。 Further explanations .