Question

I’m looking for an elegant replacement to:

if (MyMap.count(x)) return MyMap[x];

While this code does what I want — it returns an entry if one exists — in the case where the element does exist, it searches the map twice. Is there a more elegant way?

Answer 1

std::map::find() returns an iterator.

You can dereference the iterator it’s not end() with no need to search the map again.

For a trivial example:

typedef std::map<char, int> test_t;
test_t test;
test.insert(std::make_pair('a', 1));

test_t::iterator found = test.find('a');
if (found != test.end())
{
    std::cout << found->second;
}
else
{
    std::cout << "Not found";
}

Perhaps not more elegant in terms of the amount of code, but more effcient than what you currently have.