Re: Modify STL map Object
Daniel T. <daniel_t@earthlink.net> wrote:
Juha Nieminen <nospam@thanks.invalid> wrote:
Daniel T. <daniel_t@earthlink.net> wrote:
There are several issues with your code, but in the interest of brevity,
I will concentrate on your question. map::insert only inserts an object
if it doesn't already exist. Otherwise, you are expected to modify the
object that is already in place.
That's why std::map::operator[] is so handy. It allows you to insert
a new key/value pair or, if a key already existed, to modify the value,
in one single statement. Eg:
myMap["hello"] = 5;
If a key with the value "hello" didn't exist, it will be inserted and
its value will be set to 5. If it existed, the existing value will be
changed to 5.
Just keep in mind, every time you use op[] you are doing a logarithmic
search
So do std::map::find() and std::map::insert(). So what?
and in this case, if the element didn't already exist, the OP
did seem to want to add it so op[] would be inappropriate.
I don't understand. operator[] *does* add the element if it didn't
exist.
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