2016-01-23 59 views
-1

我试图循环遍历包含对象的列表。我正在使用天气API读取数据,并将每个数据成员存储为一个对象,然后将每个对象存储在一个列表中。在我存储整个列表后,我希望能够遍历列表并显示对象。我正在阅读Json的数据,我正在使用casablanca软件包来完成这项工作。我想要做的就是能够在我的main.cpp中的displayFullForcast函数中遍历我的列表。 这里是我的列表定义:在对象列表中循环

list<Weather> weather; 

这里是我的头:

​​

这是我实现:

#include "Weather.h" 
#include <list> 
#include <string> 
#include <iostream> 

using std::cout; 
using std::endl; 
using std::cin; 


Weather::Weather(double currentTemperature, double maxTemperature, double minTemperature, 
    string weatherDescription, double humidity, string time) : 
    cityState(cityState), currentTemperature(currentTemperature), highTemperature(highTemperature), lowTemperature(lowTemperature), 
    weatherDescription(weatherDescription), humidity(humidity), time(time) 
{ 
} 
Weather::Weather() 
{ 
    cityState = ""; 
    currentTemperature = 0.0; 
    highTemperature = 0.0; 
    lowTemperature = 0.0; 
    weatherDescription = ""; 
    humidity = 0.0; 
    highestTemperature = 0.0; 
    lowestTemperature = 0.0; 

} 

Weather::~Weather() 
{ 

} 

这里是我的main.cpp

void displayFullForcast() 
{ 
    list<Weather>weather; 
    for (list<Weather>::iterator it = weather.begin(); it != weather.end(); ++it) 
    { 
     cout << *it << endl; 
    } 

} 

void displayTodayForcast() 
{ 
    list<Weather>weather; 
} 

void displayLowHigh() 
{ 
    list<Weather>weather; 
} 

void displayHumidity() 
{ 
    list<Weather>weather; 
} 


void displayMenu() 
{ 
    int choice = 0; 
    cout << "What option would you like to see:\n" 
     << "(1) Forcast for 5 days\n" 
     << "(2) Forcast for Today\n" 
     << "(3) The Lowest and Highest Temperature\n" 
     << "(4) Humidity for Today\n" << endl; 
    cin >> choice; 
    switch (choice) 
      { 
      case 1: displayFullForcast(); 
       break; 
      case 2: displayTodayForcast(); 
       break; 
      case 3: displayLowHigh(); 
       break; 
      case 4: displayHumidity(); 
       break; 
      } 
} 



void executeWeatherQuery() 
{ 
    http_client client(U("http://api.openweathermap.org")); 
    uri_builder builder(U("/data/2.5/forecast")); 
    builder.append_query(U("q"), U("Searcy,AR")); 
    builder.append_query(U("appid"), U("5ee41aef99a6e283abcdd5a04d89ae67")); 
    builder.append_query(U("units"), U("imperial")); 
    builder.append_query(U("mode"), U("json")); 

    http_response response = client.request(methods::GET, builder.to_string()).get(); 
    web::json::value forecastJson = response.extract_json(true).get(); 
    web::json::value forecastListJson = forecastJson.at(U("list")); 

    if (forecastListJson.is_array()) 
    { 
     for (size_t i = 0; i < forecastListJson.size(); i++) 
     { 
      web::json::value forecastDayJson = forecastListJson[i]; 
      web::json::value mainJson = forecastDayJson.at(U("main")); 
      web::json::value currentTemperatureJson = mainJson.at(U("temp")); 
      double currentTemperature = 0; 
      if (!currentTemperatureJson.is_null()) 
      { 
       currentTemperature = currentTemperatureJson.as_double(); 
      } 
      cout << "Current Temperature " << currentTemperature << endl; 

      web::json::value weatherJson = forecastDayJson.at(U("weather"))[0]; 
      web::json::value mainWeatherJson = weatherJson.at(U("main")); 
      string weatherDescription = ""; 
      if (!mainWeatherJson.is_null()) 
      { 
       weatherDescription = conversions::to_utf8string(mainWeatherJson.as_string()); 
      } 
      cout << "Weather Description " << conversions::to_utf8string(weatherDescription) << endl; 

      web::json::value MainJson = forecastDayJson.at(U("main")); 
      web::json::value minTemperatureJson = MainJson.at(U("temp")); 
      double minTemperature = 0; 
      if (!minTemperatureJson.is_null()) 
      { 
       minTemperature = minTemperatureJson.as_double(); 
      } 
      cout << "Min Temp: " << minTemperature << endl; 

      web::json::value MainMaxJson = forecastDayJson.at(U("main")); 
      web::json::value maxTemperatureJson = MainMaxJson.at(U("temp")); 
      double maxTemperature = 0; 
      if (!maxTemperatureJson.is_null()) 
      { 
       maxTemperature = maxTemperatureJson.as_double(); 
      } 
      cout << "Max " << maxTemperature << endl; 

      web::json::value MainHumidityJson = forecastDayJson.at(U("main")); 
      web::json::value humidityJson = MainHumidityJson.at(U("humidity")); 

      double humidity = 0; 
      if (!MainHumidityJson.is_null()) 
      { 
       humidity = humidityJson.as_double(); 
      } 
      cout << "Humidity: " << humidity << endl; 

      web::json::value MainTimeJson = forecastDayJson.at(U("dt_txt")); 
      string time = ""; 
      if (!MainTimeJson.is_null()) 
      { 
       time = conversions::to_utf8string(MainTimeJson.as_string()); 

       //time = localtime(time); 
      } 
      cout << "Time" << time << endl; 

      Weather WeatherForcast(currentTemperature, maxTemperature, minTemperature, 
       weatherDescription, humidity, time); 
      list<Weather>weather; 
      weather.push_back(WeatherForcast); 
     } 
    } 
} 

void main() 
{ 
    /*string location; 
    cout << "Please enter a city and a State (Example: Searcy,AR)" << endl; 
    cin >> location;*/ 
    executeWeatherQuery(); 


displayMenu(); 
} 

**我是rec发出这个错误仍然在线上cout < < * it < < endl; 错误:没有运算符“< <”匹配这些操作数。操作数类型是std :: ofstream和Weather。

+0

我也编辑了我的代码来修复范围错误。 –

回答

1

您的问题似乎是,在你的每一个功能,您有一个单独的本地天气名单。

所以你收集的数据到一个列表被在函数结束破坏,然后显示刚创建(并且是空的)另一个列表的内容。

拥有而不是一个全球listweather。

1

我没有安装特定的天气API包,但是从你的代码,它看起来像你刚才有一个范围的问题。

在您的executeWeatherQuery中,您声明list<Weather> weather;,然后执行weather.push_back(WeatherForcast);; weather对象仅在executeWeatherQuery函数中具有本地性,因此只要该函数结束,该对象就会超出范围,并且其中的数据不再有效。此外,您的其他功能即display列表中,全部创建自己的本地list<Weather> weather;

相反,尝试为你工作在全球list<Weather> weather。这是你用静态局部(全球)天气客体主代码:

static list<Weather> weather; 

void displayFullForcast() 
{ 
    for (list<Weather>::iterator it = weather.begin(); it != weather.end(); ++it) 
    { 
     cout << *it << endl; 
    } 
} 

void displayTodayForcast() 
{ 
} 

void displayLowHigh() 
{ 
} 

void displayHumidity() 
{ 
} 


void displayMenu() 
{ 
    int choice = 0; 
    cout << "What option would you like to see:\n" 
     << "(1) Forcast for 5 days\n" 
     << "(2) Forcast for Today\n" 
     << "(3) The Lowest and Highest Temperature\n" 
     << "(4) Humidity for Today\n" << endl; 
    cin >> choice; 
    switch (choice) 
      { 
      case 1: displayFullForcast(); 
       break; 
      case 2: displayTodayForcast(); 
       break; 
      case 3: displayLowHigh(); 
       break; 
      case 4: displayHumidity(); 
       break; 
      } 
} 



void executeWeatherQuery() 
{ 
    http_client client(U("http://api.openweathermap.org")); 
    uri_builder builder(U("/data/2.5/forecast")); 
    builder.append_query(U("q"), U("Searcy,AR")); 
    builder.append_query(U("appid"), U("5ee41aef99a6e283abcdd5a04d89ae67")); 
    builder.append_query(U("units"), U("imperial")); 
    builder.append_query(U("mode"), U("json")); 

    http_response response = client.request(methods::GET, builder.to_string()).get(); 
    web::json::value forecastJson = response.extract_json(true).get(); 
    web::json::value forecastListJson = forecastJson.at(U("list")); 

    if (forecastListJson.is_array()) 
    { 
     for (size_t i = 0; i < forecastListJson.size(); i++) 
     { 
      web::json::value forecastDayJson = forecastListJson[i]; 
      web::json::value mainJson = forecastDayJson.at(U("main")); 
      web::json::value currentTemperatureJson = mainJson.at(U("temp")); 
      double currentTemperature = 0; 
      if (!currentTemperatureJson.is_null()) 
      { 
       currentTemperature = currentTemperatureJson.as_double(); 
      } 
      cout << "Current Temperature " << currentTemperature << endl; 

      web::json::value weatherJson = forecastDayJson.at(U("weather"))[0]; 
      web::json::value mainWeatherJson = weatherJson.at(U("main")); 
      string weatherDescription = ""; 
      if (!mainWeatherJson.is_null()) 
      { 
       weatherDescription = conversions::to_utf8string(mainWeatherJson.as_string()); 
      } 
      cout << "Weather Description " << conversions::to_utf8string(weatherDescription) << endl; 

      web::json::value MainJson = forecastDayJson.at(U("main")); 
      web::json::value minTemperatureJson = MainJson.at(U("temp")); 
      double minTemperature = 0; 
      if (!minTemperatureJson.is_null()) 
      { 
       minTemperature = minTemperatureJson.as_double(); 
      } 
      cout << "Min Temp: " << minTemperature << endl; 

      web::json::value MainMaxJson = forecastDayJson.at(U("main")); 
      web::json::value maxTemperatureJson = MainMaxJson.at(U("temp")); 
      double maxTemperature = 0; 
      if (!maxTemperatureJson.is_null()) 
      { 
       maxTemperature = maxTemperatureJson.as_double(); 
      } 
      cout << "Max " << maxTemperature << endl; 

      web::json::value MainHumidityJson = forecastDayJson.at(U("main")); 
      web::json::value humidityJson = MainHumidityJson.at(U("humidity")); 

      double humidity = 0; 
      if (!MainHumidityJson.is_null()) 
      { 
       humidity = humidityJson.as_double(); 
      } 
      cout << "Humidity: " << humidity << endl; 

      web::json::value MainTimeJson = forecastDayJson.at(U("dt_txt")); 
      string time = ""; 
      if (!MainTimeJson.is_null()) 
      { 
       time = conversions::to_utf8string(MainTimeJson.as_string()); 

       //time = localtime(time); 
      } 
      cout << "Time" << time << endl; 

      Weather WeatherForcast(currentTemperature, maxTemperature, minTemperature, 
       weatherDescription, humidity, time); 
      weather.push_back(WeatherForcast); 
     } 
    } 
} 

void main() 
{ 
    /*string location; 
    cout << "Please enter a city and a State (Example: Searcy,AR)" << endl; 
    cin >> location;*/ 
    executeWeatherQuery(); 
    displayMenu(); 
} 

注意如何只有一个weather多数民众赞成操作上的文件范围内的对象,而不是每个功能一个weather对象。

希望能有所帮助。

0

除了范围界定问题,其他人所说的,你还需要编写一个函数来打印对象:

std::ostream& operator <<(std::ostream& str, const Weather & w) 
{ 
    str << "Temp will be " << w.temp << std::endl; 
} 

您还需要使这个函数类的朋友。

(写在手机上。编辑完成欢迎功能。)