Question

Often times you see things like

std::map<std::string, somethingelse> m_named_objects;

or

std::string state;

//...

if(state == "EXIT")
   exit();
else if(state == "california")
   hot();

where people use strings purely to make something more readable. The same thing could easily be achieved with something like integer-IDs.

Can modern compilers (msvc, g++, etc.) usually employ special optimizations for these types of cases? Or should this be avoided because of bad performance or for other reasons?

Answer 1

Can modern compilers (msvc, g++, etc.) usually employ special optimizations for these types of cases?

As far as I know, compilers don’t make those kinds of optimizations. It’s definitely not a “standard” optimization.

…where people use strings purely to make something more readable.

At least for your second case, it seems to me that enumerations are more readable and can be faster (since integer comparisons are rather cheap relative to string comparison).

enum State
{
    Alabama,
    Alaska,
    Arizona,
    Arkansas, 
    California,
    Colorado,
    Connecticut,
    Delaware,
    // ... More
};

// ...

State state = California;
if(state == California) { /* true */ }