vector.resize

void resize ( size_type sz, T c = T() );

Change size

Resizes the vector to contain  sz elements.

If  sz is smaller than the current vector  size, the content is reduced to its first  sz elements, the rest being dropped.

If  sz is greater than the current vector  size, the content is expanded by inserting at the end as many copies of  c as needed to reach a size of  sz elements. This may cause a reallocation.

Notice that this function changes the actual content of the vector by inserting or erasing elements from the vector; It does not only change its storage  capacity. To direct a change only in storage capacity, use  vector::reserveinstead.