C++ STL:map,string

#include 
#include "map"
#include "string"
#include "fstream"
std::map readImageNetLabel(const std::string &fileName)
{
    std::map imagenetLabel;
    std::ifstream  file(fileName);
    if (!file.is_open())
    {
        std::cout<<"read file error"< label;
    label= readImageNetLabel(fileDir);
    std::map::iterator iter;
    for(iter=label.begin();iter!=label.end();iter++)
    {
        std::cout<<"key: "<first<<" value: "<second< 
其中label.txt内容如下：
 
0: 'close'
1: 'open'
 
注：
 
label.txt文本中不可以存在空行，否则会报以下错误：
 
terminate called after throwing an instance of 'std::out_of_range'
  what():  basic_string::substr: __pos (which is 2) > this->size() (which is 0)
 
错误情形：
 
0: 'close'
1: 'open'