Question

这是家庭作业。因此，无论如何，该练习要求用户读取csv文件，通过Template Vector类使用内部数据（风速）进行计算，并显示平均风速以及其他一些信息。问题在于如何将文件读入向量类以执行计算。

我一直不成功，使用getline和stringstream隔离特定值（在10个逗号之后）。问题是当我尝试将值与Template Vector类一起使用时。诸如push_back（）和size（）之类的某些功能有效，但是at（）和print（）却遇到问题。

// included all the necessary .h and <> here
typedef struct
{
    Date d;
    Time t;
    float speed;
} WindLogType;

// declare speed max function (I just realised I have no idea what this was for)
ostream & operator << (ostream & osObject, const WindLogType & W1);
istream & operator >> (istream & input, WindLogType & W1);

int main()
{
    // Declared a lot of variables here etc.

    Vector <WindLogType> windlog;

    WindLogType transfer; // Declaring an object of WindLogType

    while(getline(input, line))
    {
        stringstream line2(line);
        string cell; // Denotes a particular column
        int col = 0;

        while(getline(line2, cell, ','))
        {
            if(col == 10)
            {
                speed = atof(cell.c_str()); // Converting to c-string, and 
                                            // then float

                transfer.speed = speed; // Inputting wind speed into 
                                        // WindLogType speed

                windlog.push_back(transfer);
            }
            col++;
        }
    }

    // Sum of all the wind speeds
    for(int i = 0; i < windlog.size(); i++)
    {
        sum = sum + (windlog.at(i) * 3.6); // Converting every elements to 
                                           // km/h
    }

    average = sum/windlog.size(); // Average wind speed
    cout << average;

    while(input.eof())
    {
        ...;
    }

    // Printing out date and time of speeds that be equal to the average
    for(int j = 0; j < windlog.size(); j++)
    {
        if(windlog.at(j) == average)
        {
            ...;
        }
    }

    input.close();
}

// In the Template Vector Class
template <class Type>
class Vector
{
   Type *list;
   int length; // The number of arrays of a current vector.
   void push_back(const Type& i);
   ...; // Everything else
}

template <class Type>
Type& Vector<Type>::at(int i)
{
    if((i >= 0) && (i < length))
    {
        return list[i];
    }

    return list[0];
}

我希望sum = sum + (windlog.at(i) * 3.6)或if(windlog.at(j) == average)可以正常工作，但是它返回error: no match for 'operator*' (operand types are 'WindLogType' and 'double')。

那么我是如何将csv文件读入向量的呢？

C ++错误：“ operator *”不匹配（操作数类型为“ WindLogType”和“ double”）

0 个答案: