c++ - 文件 IO 从文件中读取多种类型

Question

假设我有一个像这样的文本文件

6 3
john
dan
lammar

我可以读取数字，并且只有在单独的文件中才能读取名称。但是这里的数字和名称都在一个文件中。我如何忽略第一行并直接从第二行开始阅读？

int main()
{
vector<string> names;
fstream myFile;
string line;
int x,y;
myFile.open("test.txt");
    //Im using this for reading the numbers
while(myFile>>x>>y){}
//Would use this for name reading if it was just names in the file
while(getline(myFile,line))
    names.push_back(line);
cout<<names[0];
return 0;
}

Answer 1

我不确定我是否正确，但如果你总是想跳过第一行 - 你可以简单地跳过它吗？

int main()
{
    vector<string> names;
    fstream myFile;
    string line;
    int x,y;
    myFile.open("test.txt");
    //skip the first line
    myFile>>x>>y;
    //Would use this for name reading if it was just names in the file
    while(getline(myFile,line))
    names.push_back(line);
    cout<<names[0];
    return 0;
}

Answer 2

如果您使用 fstream，只需调用 ignore() 方法：

istream&  ignore ( streamsize n = 1, int delim = EOF );

所以它变得非常容易：

ifstream file(filename);
file.ignore(numeric_limits<streamsize>::max(), '\n');    // ignore the first line

// read the second line
string name; getline(flie, name);

Answer 3

尝试这样的事情：

int main()
{
    std::vector<std::string> names;
    std::fstream myFile;
    myFile.open("test.txt");
    if( myFile.is_open() )
    {
        std::string line;

        if (std::getline(myFile, line))
        {
            std::istringstream strm(line);

            int x, y;
            strm >> x >> y;

            while (std::getline(myFile, line))
                names.push_back(line);
        }

        myFile.close();

        if( !names.empty() )
            std::cout << names[0];
    }
    return 0;
}