stl - deleting elements completely from multimap (C++) -

so have multimap, key struct, , values struct.

multimap<struct, struct> multimap1; 

multimap1 contains (format key: value)

1: random value 1 2: random value 2 3: random value 3 4: random value 4 

i trying erase value , key multimap. let's want remove second entry of multimap. result should this:

1: random value 1 3: random value 3 4: random value 4 

i have iterator points second value, when erase using multimap1.erase(it), should remove second entry (at least think should). have been reading on removing entries , multimaps , seems value removed multimap, not key. if erase second entry iterator pointing second value, (correct me if wrong):

1: random value 1 2:  3: random value 3 4: random value 4 

is there way middle value result?

edit: apparently wrong. if erase, middle result. trying figure why not erasing correctly because, code segfaults when call erase. if call it->first, returns key of element want removed. if call it->second, returns value of key. if call multimap.erase(it), should remove entire thing, correct?

edit 2: in code, printed out it->first , it->second make sure pointer pointing correct element , was. when called multimap.erase(it), stopped loop , printed out remaining elements in multimap. prints first element correctly, second element printed (output compiler):

gewolfc?`6??2?x3??2??2?x 1@4?????buya????badwolfcorp1????amstykrq?4?x3??(4??3?     x3planetexpress1geqp7?l???5?d?5?x5??5?d2q7?7?x3??(4??3?x3?? 

so obviously, not deleting correctly. running g++ 4.7 on linux.

edit 3: sorry many edits, want keep original question people can reference in future. experiment, called multimap.erase(it->first) , worked correctly. can explain me why worked , going on here?

erase remove whole entry (the "key-value" pair), want.

sometimes, confusion arises when talking map types since library specification defines value_type mean "key-value" pair, not "value" (which defined mapped_type); word "value" used interchangabley mean 1 or other.