c++：没有过载 function 的实例？

Question

// stock.h

#ifndef STOCK_H
#define STOCK_H

// declare Stock Class
class Stock
{
private:
    string StockExchange;
    string Symbol;
    string Company;
    double Price;
    int Shares;
public:
    Stock();
    Stock(string stockExchange, string symbol, string company, double price, int shares);
    void displayStockInfo();
    void setStockInfo(string stockExchange, string symbol, string company, double price, int shares);
    double getValue();
    bool operator < (Stock & aStock);
    bool Stock::operator > (Stock & aStock);
};

#endif

[break]

//main.cpp

#include <string>
#include <iostream>
#include <iomanip>
#include <fstream>

#include "stock.h"

using std::string;
using std::endl;
using std::cout;
using std::setw;
using std::ifstream;


// *******************************
// Stock class

Stock::Stock() {
    StockExchange = "";
    Symbol = "";
    Company = "";
    Price = 0.0;
    Shares = 0;
}

Stock::Stock(string stockExchange, string symbol, string company, double price, int shares) {
    StockExchange = stockExchange;
    Symbol = symbol;
    Company = company;
    Price = price;
    Shares = shares;
}


// end Stock class
// *******************************

...

My error says something along the lines of "no instance of overloaded function Stock::Stock(string stockExchange, string symbol, string company, double price, int shares) exists."

What am I doing wrong? I see it in my header file.

Answer 1

You've not included <string> header file in stock.h header file, even though you're using std::string in it. Maybe that is causing this error message (if that is the case, then I would say its really a bad message).

Another problem is that in Stock class definition, you've written this:

bool Stock::operator > (Stock & aStock);

which is wrong. Remove Stock:: from it, and make it like this:

bool operator > (const Stock & aStock);
               //^^^^ add this also (better)

Stock:: is required when defining the function outside the class.