Question

我在高级面向对象编程课程中真的需要帮助！以下是该计划的运作方式;我们用C ++编写代码，我们要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'，如果你会给你当前的天气读数;如果你按'3'它会给你天气历史;如果按'4'则退出。此外，它从文本文件中读取输出并将它们输出到控制台...我已经完全正常工作了。我遇到的问题是我们要重载流（＆lt;＆lt;＆gt;＆gt;）运算符，所以我们不再需要调用print（）函数。以前，我打印打印功能打印当前的天气读数以及温度历史记录。我已经排除了我的文件wind.h和wind.cpp，因为我还没有开始尝试在那里实现重载;加上我想我在一篇文章中发布了足够的代码。此外，我应该提一下，如果用户想要使用piglatin.txt中的英语或染色剂，如果他们想要使用piglatin，该程序还会读取english.txt的输出。

我的问题，基本上，我是如何正确实现运算符流的重载？

Source.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

Temp.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
    }*/

Temp.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

Answer 1

因此。这是第一点。他的评论完全正确。您的问题中存在吨不相关的代码。

所以，首先，让我们删除它。并将问题的范围缩小到有人可能会阅读的大小。

#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，但删除了您的注释之类的内容（为什么我关心您的温度等级将来会使用F / C比较）。另外，让我们摆脱你所有的菜单结构。我也不在乎，你声称它工作正常。

所以，现在我们需要查看合理数量的代码，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;
}

如果我们执行此....

[2:48pm][wlynch@watermelon /tmp] ./foo
123
Temperature(123)
[2:48pm][wlynch@watermelon /tmp] ./foo
-9000
Temperature(-9000)

在C ++中重载我的流操作符的主要问题

1 个答案: