我无法让我的程序在函数中读取我的文件

Question

I can't seem to figure out why my code is not reading in the data to use in a switch case. When I write it to a file, it just pulls up garbage. Can anyone help?

void readData(Name element[], int size)
{
    ifstream infile("treeData.txt");

    int index = 0;
    string line, common, scientific, family;
    int name;

    infile.open("treeData.txt");
    {           
        {
            while((index < size) && (infile >> name >> common >> scientific >> family))
            {
                if(name >= 0 && name <= 100)
                {
                    infile >> element[index].treeID;
                    element[index].treeID = name;
                    infile >> element[index].commonName;
                    element[index].commonName = common;
                    infile >> element[index].scientificName;
                    element[index].scientificName = scientific;
                    infile >> element[index].familyName;
                    element[index].familyName = family;
                    index++;
                    size = index;
                }   
                else
                    cout << "The file was not found!";
            }
        }
    }       
    infile.close();
}

Answer 1

Your implementation should take advantage of the extensibility features of the C++ IOStreams library. You can create an overload of operator >> so that any input stream can extract data into a Name object. It's also advised that instead of extracting the data into an array (like you've attempted in your readData function) you extract it into a single object. That way code can be built on top of this functionality. It's also a more logical and straighforward way of performing extraction:

std::istream& operator>>(std::istream& is, Name& n)
{
    if (!is.good())
        return is;

    int id;
    std::string line, common, scientific, family;

    if (is >> id >> common >> scientific >> family)
    {
        if (id >= 0 && id <= 100)
            n.treeID = id;

        n.treeID         = name;
        n.commonName     = common;
        n.scientificName = scientific;
        n.familyName     = family;
    }
    return is;
}

Now that we have our extractor, we can go ahead and create an array of Name objects and use the extractor for each element:

std::ifstream infile("treeData.txt");
std::array<Name, 5> names;

for (auto name : names)
{
    infile >> name;
}