why doesn't erase method for map take key value as its parameter?

[yaru22]

When I look at the C++ reference, erase method for map takes an
iterator as a parameter. I'm wondering why it takes iterator instead
of key value. Wouldn't it be faster to take key value and erase the
object? (because lookup operation using key value would be faster than
creating an iterator and iterate through the map?)

[John Harrison]

yaru22 wrote:

When I look at the C++ reference, erase method for map takes an
iterator as a parameter. I'm wondering why it takes iterator instead
of key value. Wouldn't it be faster to take key value and erase the
object? (because lookup operation using key value would be faster than
creating an iterator and iterate through the map?)

When you look up a key, you are getting the iterator for that key. So
obviously deleteing using an iterator must be faster than looking to the
key to get the iterator and then using the iterator to delete.

john

[Victor Bazarov]

yaru22 wrote:

When I look at the C++ reference, erase method for map takes an
iterator as a parameter. I'm wondering why it takes iterator instead
of key value. Wouldn't it be faster to take key value and erase the
object? (because lookup operation using key value would be faster than
creating an iterator and iterate through the map?)

Sorry... What reference are you looking at that doesn't have the 'erase'
member of 'std::map' that takes a key value?

V
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