Question

I need to get the first character of an std::string with a minimum amount of code.

It would be great if it would be possible to get the first char in one line of code, from an STL std::map<std::string, std::string> map_of_strings. Is the following code correct:

map_of_strings["type"][0]

EDIT
Currently, I am trying to use this piece of code. Is this code correct?

if ( !map_of_strings["type"].empty() )
    ptr->set_type_nomutex( map_of_strings["type"][0] );

The prototype of the set_type function is:

void set_type_nomutex(const char type);

Answer 1

It’s not exactly clear from your question what your problem is, but the thing likely to go wrong with map_settings["type"][0] is that the returned string may be empty, resulting in undefined behavior when you do [0]. You have to decide what you want to do if there is no first character. Here’s a possibility that works in a single line.

ptr->set_type_nomutex( map_settings["type"].empty() ? '\0' : map_settings["type"][0]);

It gets the first character or a default character.