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在我的高级面向对象编程课程中，我真的需要帮助！这是该程序的工作原理；我们正在用 C++ 编写代码，我们将创建一个创建气象站的程序。如果按“1”，则输入温度、风速和风向；如果你按'2'如果会给你当前的天气读数; 如果您按“3”，它将为您提供天气历史；如果按“4”，则退出。此外，它还从文本文件中读取输出并将它们输出到控制台……我让所有这些都正常工作。我遇到的问题是我们要重载流（<< 和 >>）运算符，因此我们不再需要调用 print() 函数。以前，我调用了 print 函数来打印当前的天气读数以及温度历史。我已经排除了我的文件 wind.h 和 wind。cpp，因为我什至还没有开始尝试在那里实现重载；另外，我认为我在一篇文章中发布了足够的代码。另外，我应该提到，如果用户想要英语，该程序还会从english.txt 读取输出，如果他们想要piglatin，则从piglatin.txt 读取piglation。

基本上，我的问题是如何正确实现运算符流的重载？

源.cpp：

#include <iostream>
#include <string>
#include "temp.h"
#include "Wind.h"
#include "Language.h"
#include <fstream>
#define SIZE 10
using namespace std;

int main()
{
    Temperature temp1;
    win wind1;
    //Temperature p;
    string windDir[SIZE];
    int windSpeed[SIZE];
    int temp[SIZE];
    //Tem p1(int temp);
    int index=0;
    int reply;
    int reply2;
    int lang;
    int count=0;
    string STRING1, STRING2, STRING3, STRING4, STRING5, STRING6;
    fstream myEngFile;
    fstream myPigFile;
    ofstream out;

    //Language Menu
    cout<<"**** Welcome to The Michael Weather Station! \n";
    cout<<"**** Elcomeway otay Ethay Ichaelmay Eatherway Ationstay! \n";
    cout<<"Please enter 1 for english ";
    cout<<"orway 2 orfay iglatinpay \n";
    cin>>lang;
    cin.clear();

    switch(lang){

        //English Main Menu
    case 1:
    //for(int count=0; count<21; count++)
    for(int index=0; index<SIZE; index++){
    bool menu = true;
    while (menu != false){
    myEngFile.open ("English.txt");
    getline(myEngFile, STRING1);
    cout<<STRING1<<"\n";
    getline(myEngFile, STRING2);
    cout<<STRING2<<"\n";
    getline(myEngFile, STRING3);
    cout<<STRING3<<"\n";
    getline(myEngFile, STRING4);
    cout<<STRING4<<"\n";
    getline(myEngFile, STRING5);
    cout<<STRING5<<"\n";
    cin>>reply;
    cin.clear();
    myEngFile.close();

    switch(reply){

        //Gets data in English
    case 1:
    temp[count]=temp1.getTemp();
    windSpeed[count] =wind1.getSpeed();
    windDir[count] = wind1.getDirection();
    cout<<" \n";
    count++;
    break;

    //Prints data in English
    case 2:
        cout<<"--------------------------------\n";
    //temp1.printTemp(temp[count-1]);
        Temperature p = temp1.getTemp();
    //cout<<temp[count-1];
        cout<<p;
    wind1.printWindMeasurement(windSpeed[count-1], windDir[count-1]);
    cout<<" \n";
    cout<<" \n";
    break;

    //Prints History in English 
    case 3:
        cout<<"---------------------------------- \n";
    //for(int index=SIZE%count; index<SIZE; index++){
    for(int i=0; i<count; i++){
    //temp1.printTemp(temp[i]);
    cout<<temp[i];
    wind1.printWindMeasurement(windSpeed[i], windDir[i]);
    cout<<"\n";
    }
        break;

        //Exits...In English?
    case 4:
        cout<<"Exiting............. \n";
        menu= false;
        break;

        //Cheacks to see that only 1,2,3, or 4 is entered
    default:
        cout<<"Please enter 1,2,3, or 4 only!!! \n";
        cout<<" \n";

    } //Switch(reply) in english

    } //While loop in english

    return 0;

} //For loop in english

    break;

    //PigLatin Main Menu
    case 2:
    for(int index=0; index<SIZE; index++){
    bool menu = true;
    while (menu != false){
    myPigFile.open ("PigLatin.txt");
    getline(myPigFile, STRING1);
    cout<<STRING1<<"\n";
    getline(myPigFile, STRING2);
    cout<<STRING2<<"\n";
    getline(myPigFile, STRING3);
    cout<<STRING3<<"\n";
    getline(myPigFile, STRING4);
    cout<<STRING4<<"\n";
    getline(myPigFile, STRING5);
    cout<<STRING5<<"\n";
    getline(myPigFile, STRING6);
    cout<<STRING6<<"\n";
    cin>>reply2;
    cin.clear();
    myPigFile.close();


    switch(reply2){

        //Gets data in PigLatin
    case 1:
    temp[count]=temp1.getTemp2();
    windSpeed[count] =wind1.getSpeed2();
    windDir[count] = wind1.getDirection2();
    cout<<" \n";
    count++;
    break;

    //Prints data in PigLatin
    case 2:
        cout<<"----------------------------------\n";
    //temp1.printTemp2(temp[count-1]);
    cout<<temp[count-1];
    wind1.printWindMeasurement2(windSpeed[count-1], windDir[count-1]);
    cout<<" \n";
    cout<<" \n";
    break;

    //Prints History in PigLatin
    case 3:
        cout<<"------------------------------------ \n";
    //for(int index=SIZE%count; index<SIZE; index++){
    for(int i=0; i<count; i++){
    //temp1.printTemp2(temp[i]);
    cout<<temp[i];
    wind1.printWindMeasurement2(windSpeed[i], windDir[i]);
    cout<<"\n";
    }
        break;

        //Exits...in PigLatin?
    case 4:
        cout<<"exitingway............. \n";
        menu= false;
        break;

        //Checks to see only 1,2,3, or 4 is entered
    default:
        cout<<"Easeplay enterway 1,2,3, orway 4 onlyway!!! \n";
        cout<<" \n";

    } //Switch (Reply2) in piglatin

    } //While loop for PigLatin Main Menu

    return 0;

} //For loop for PigLatin Main Menu

break;

} //switch(Lang)

} //Main

温度.cpp：

#include "temp.h"
#include "Language.h"

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

//        Lang La;
        fstream myEngFile5;
        string tempLine5;
        string tempLine6;
        //string tempLine1; // from language file


        /**** Keep the getTemp() method, but get rid of the print method 
        and overload the operators there*******/

ostream &operator<<( ostream &out, const Temperature &p) //&f
{
    //int far=0;
    fstream myEngFile1;
    string tempLine1;
    myEngFile1.open ("English.txt");
    myEngFile1.seekg(194);
    getline(myEngFile1, tempLine1);
    //La.getTempLang();
    out<<p.tempLine1<<endl; // What is the Temperature?
//  cin>>p; //f
    return out;
    //myEngFile1.close();
    }



/*int Temperature::getTemp()
{
    int value=0;
    fstream myEngFile1;
    string tempLine1;
    myEngFile1.open ("English.txt");
    myEngFile1.seekg(194);
    getline(myEngFile1, tempLine1);
    cout<<tempLine1<<"\n"; // What is the Temperature?
    cin>>value;
    return value;
    myEngFile1.close();
    }*/

int Temperature::getTemp2()
{
    int value=0;
    fstream myPigFile1;
    string tempLine1;
    myPigFile1.open ("PigLatin.txt");
    myPigFile1.seekg(254);
    getline(myPigFile1, tempLine1);
    cout<<tempLine1<<"\n"; //What is the Temperature? in piglatin
    cin>>value;
    return value;
    myPigFile1.close();
    }

/*void Tem::printTemp(int temper)
    {
        fstream myEngFile5;
        string tempLine5;
        string tempLine6;
        myEngFile5.open("English.txt");
        myEngFile5.seekg(335);
        getline(myEngFile5, tempLine5);
        cout<<tempLine5<<temper; //The Temperature is
        myEngFile5.seekg(356);
        getline(myEngFile5, tempLine6);
        cout<<tempLine6<<"\n"; //F
    }*/

ostream &operator<<( ostream &out, const Temperature p)
{    
        out<<tempLine5<<p.value; //The Temperature is __
        out<<tempLine6<<"\n"; //F
        return out;
}

istream &operator>>( istream &in, Temperature &p)
{
        //in>>p.value;
        myEngFile5.open("English.txt");
        myEngFile5.seekg(335);
        getline(myEngFile5, tempLine5);
        in>>tempLine5;
        myEngFile5.seekg(356);
        getline(myEngFile5, tempLine6);
        in>>tempLine6;
        return in;
}

/*void Tem::printTemp2(int temper)
    {
        fstream myPigFile4;
        string tempLine5;
        string tempLine6;
        myPigFile4.open("PigLatin.txt");
        myPigFile4.seekg(445);
        getline(myPigFile4, tempLine5);
        cout<<tempLine5<<temper; //The temperature is __ (in piglatin) 
        myPigFile4.seekg(473);
        getline(myPigFile4, tempLine6);
        cout<<tempLine6<<"\n"; //fay
    }*/

温度.h：

#ifndef TEMP
#define TEMP
#include <fstream>
#include <string>

using namespace std;

//int index=0;

class Temperature 
{
    int value;
    //char unit;

public:

    string tempLine1;

int getTemp();
int getTemp2();

Temperature()
{
value=0;
//unit='F';
}

Temperature(int v/*, char u*/)
{
    value=v;
    //unit=u;
}
friend ostream &operator<<(ostream &out, const Temperature &p); // needs 'friend' i think
friend istream &operator>>(istream &in, Temperature &p);
//friend ostream operator<<(ostream out, const Temperature p);
//friend istream operator>>(istream in, Temperature &p);

//void printTemp(int temper);
//void printTemp2(int temper);
};

#endif
4

1 回答 1

1

所以。这是第一点。mah 的评论完全正确。您的问题中有大量不相关的代码。

所以，首先，让我们删除它。并将您的问题的范围缩小到有人可能愿意阅读的大小。

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

using namespace std;

class Temperature
{
    private:
        int value;

    public:
        Temperature(): value(0) {
        }

        explicit Temperature(int v): value(v) {
        }

        friend ostream &operator<<(ostream &out, const Temperature &p);
        friend istream &operator>>(istream &in, Temperature &p);
};

ostream &operator<<(ostream &out, const Temperature &p)
{
    fstream myEngFile1;
    string tempLine1;
    myEngFile1.open ("English.txt");
    myEngFile1.seekg(194);
    getline(myEngFile1, tempLine1);
    out << p.tempLine1 << endl; // What is the Temperature?
    out << tempLine5 << p.value; //The Temperature is __
    out << tempLine6 << "\n"; //F
    return out;
}

istream &operator>>( istream &in, Temperature &p)
{
    //in>>p.value;
    myEngFile5.open("English.txt");
    myEngFile5.seekg(335);
    getline(myEngFile5, tempLine5);
    in>>tempLine5;
    myEngFile5.seekg(356);
    getline(myEngFile5, tempLine6);
    in>>tempLine6;
    return in;
}

int main() {
    Temperature x;
    std::cin >> x;
    std::cout << x << std::endl;
}

这或多或少是您的代码，但是删除了您的评论之类的内容（我为什么关心您的温度等级将来会使用 F/C 比较）。此外，让我们摆脱所有的菜单结构。我也不在乎，你声称它工作正常。

所以，现在我们有相当数量的代码可供查看，所以让我们展示一个合理的 ostream 和 istream 重载实现。

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

class Temperature
{
    private:
        int value;

    public:
        Temperature(): value(0) {
        }

        explicit Temperature(int v): value(v) {
        }

        friend std::ostream &operator<<(std::ostream &out, const Temperature &p);
        friend std::istream &operator>>(std::istream &in, Temperature &p);
};

std::ostream &operator<<(std::ostream &out, const Temperature & p)
{
    out << "Temperature(" << p.value << ")";
    return out;
}

std::istream &operator>>( std::istream &in, Temperature &p)
{
    in >> p.value;
    return in;
}

int main() {
    Temperature x;
    std::cin >> x;
    std::cout << x << std::endl;
}

如果我们执行这个......

[2:48pm][wlynch@watermelon /tmp] ./foo
123
Temperature(123)
[2:48pm][wlynch@watermelon /tmp] ./foo
-9000
Temperature(-9000)
于 2013-11-13T20:47:38.027 回答