LowerBound in multiset stl

Question

I was trying to find how many element are less than a certain X in a multiset by using:

mset.lower_bound(X) - mset.begin()

But it didn't work. Any workarounds?

Answer 1

You may use:

std::distance(mset.begin(), mset.lower_bound(X));

To make it robust, use:

size_t count = 0;
auto found = mset.lower_bound(X);
if ( found != mset.end() )
{
   count = std::distance(mset.begin(), found);
}