Does a vector array resize after erasing one/more elements?

Question

Does vector.erase resize the vector object so that I can measure the reduced size with vector.size()?

for example;

vector<int> v(5);
v = {1,2,3,4,5};

and I want to delete 4 by;

v.erase(v.begin()+4);

Does my vector object v have a size of 4 now. In other words is v.size() == 4 after this operation?

Answer 1

Yes, size is decreased as you erase elements.

---

Don't be afraid to test yourself though, by writing a minimal example, like this :) :

#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> v(5);
    v = {1,2,3,4,5};
    cout << v.size() << endl;
    v.erase(v.begin()+4);
    cout << v.size() << endl;
    return 0;
}

you would get:

gsamaras@gsamaras-A15:~$ g++ -Wall -std=c++0x main.cpp 
gsamaras@gsamaras-A15:~$ ./a.out 
5
4

And we would expect that right? I mean the ref says:

Return size

Returns the number of elements in the vector.

This is the number of actual objects held in the vector, which is not necessarily equal to its storage capacity.