Question

我对C ++很陌生，我们正在使用链表和类。我的程序主要工作，但我的voidCalc函数给出了错误：

error LNK2019: 
unresolved external symbol "void __cdecl calcData(class WeatherStats * const,int)"
(?calcData@@YAXQAVWeatherStats@@H@Z) 
referenced in function _main

我只包含主文件，如果你需要其他两个标题，我可以添加它们。谢谢!!

#include "LinkedList.h"
#include "WeatherStats.h"
#include <iostream>
#include <iomanip>
using namespace std;

//Function prototype for highest/lowest
void calcData (WeatherStats stats[], int SIZE);

int main()
{

LinkedList<WeatherStats> weather;
WeatherStats stats;
double rain, snow;
int sun, months;

cout << "Please enter the number of months you would like to report on.\n";
cin >> months;
stats.setMonths(months);

for(int count = 0; count < months; count++)
{
    //Get the information from the user
    stats.setMonths(count+1);
    cout << "Please enter the amount of snow for month " << (count+1) << endl;
    cin >> snow;
    stats.setSnow(snow);
    cout << "Please enter the amount of rain for month " << (count+1) << endl;
    cin >> rain;
    stats.setRain(rain);
    cout << "Please enter the amount of sunny days for month " << (count+1) <<     endl;
    cin >> sun;
    stats.setSun(sun);
    cout << endl;

    //Add the node
    weather.appendNode(stats);
}

weather.displayList();

calcData(&stats, months);

return 0;
}

void calcData (WeatherStats *stats[], int SIZE)
{
int highSun = 0;
int highSunMonth, lowSunMonth, highRainMonth, lowRainMonth, highSnowMonth, lowSnowMonth;
int lowSun = 0;
double lowRain = 0;
double highRain = 0;
double lowSnow = 0;
double highSnow = 0;

for (int count = 1; count <= SIZE; count++)
{
    //Highest Sun and its month
    if(highSun < stats[count]->getSun())
    { highSun = stats[count]->getSun(); 
      highSunMonth = stats[count]->getMonths();
    }

    //Lowest sun and its month
    if (lowSun > stats[count]->getSun())
    { lowSun = stats[count]->getSun();
        lowSunMonth = stats[count]->getMonths();
    }

    //Highest rain and its month
    if(highRain < stats[count]->getRain())
    {
        highRain = stats[count]->getRain();
        highRainMonth = stats[count]->getMonths();
    }

    //Lowest rain and its month
    if (lowRain > stats[count]->getRain())
    {
        lowRain = stats[count]->getRain();
        lowRainMonth = stats[count]->getMonths();
    }

    //Highest snow and its month
    if (highSnow < stats[count]->getSnow())
    {
        highSnow = stats[count]->getSnow();
        highSnowMonth = stats[count]->getMonths();
    }

    //Lowest snow and its month
    if (lowSnow > stats[count]->getSnow())
    {
        lowSnow = stats[count]->getSnow();
        lowSnowMonth = stats[count]->getMonths();
    }

    //Output findings
    cout << "The month with the most sun was Month " << highSunMonth << " with " << highSun << " days.\n";
    cout << "The month with the least sun was Month " << lowSunMonth << " with " << lowSun << " days.\n";
    cout << "The month with the most rain was Month " << highRainMonth << " with " << highRain << " units.\n";
    cout << "The month with the least rain was Month " << lowRainMonth << " with " << lowRain << " units.\n";
    cout << "The month with the most snow was Month " << highSnowMonth << " with " << highSnow << " units.\n";
    cout << "The month with the least snow was Month " << lowSnowMonth << " with " << lowSnow << " units.\n";
}
}

Answer 1

您的函数原型是：

void calcData (WeatherStats stats[], int SIZE);

您的功能声明是：

void calcData (WeatherStats *stats[], int SIZE) { ... }

那些不一样。

Answer 2

尝试像这样声明calcData函数：

void calcData (WeatherStats *stats[], int SIZE);

或者这个：

extern "C" void calcData (WeatherStats *stats[], int SIZE);

（请注意添加额外的明星。）

如果这没有帮助，请确保在链接器命令行（或IDE项目设置的依赖项列表）中包含定义此函数的库（.lib或.dll）。

Answer 3

您的功能原型和实际功能存在差异。

void calcData (WeatherStats stats[], int SIZE);
void calcData (WeatherStats *stats[], int SIZE);

请注意，实际的函数签名中有*，原型中没有。

C ++“未解析的外部符号”用于main之外的函数

3 个答案: