CODEWITHSUNDEEP
c++stliterator
Aminos
Aminos

Reputation: 871

using erase with remove_if

This thing drive me crazy, I couldn't understand it :

// v contains : 101, 1, 2, 3, 4 , 5
v.erase(remove_if(v.begin(), v.end(), bind2nd(less<int>(), 3)), v.end());
// v contains now : 101, 3, 4, 5

Why there is v.end() as a second argument in erase ?? I read that remove_if returns an iterator to the element that follows the last element not removed, what does it mean.... v.erase(v.begin(), v.end()) should erase all the vector elements, but how in the example above it does not erase 3, 4 and 5 ? how this thing works ? I didn't find something edifiying about it in the internet.

Upvotes: 1

Views: 202

Answers (1)

NathanOliver
NathanOliver

Reputation: 180650

remove doesn't actually remove any elements in the vector but it moves them to the end of the vector. It then returns an iterator to the new last element which is the first "removed" element. You then erase from that iterator to the end of the vector to actually get rid of the elements in the vector.

Upvotes: 9

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