STL's vector resizing

c++, stl, vector

Solution

From MSDN reference1

If the container's size is less than the requested size, _Newsize, elements are added to the vector until it reaches the requested size. If the container's size is larger than the requested size, the elements closest to the end of the container are deleted until the container reaches the size _Newsize. If the present size of the container is the same as the requested size, no action is taken

The ISO C++ standard (page 485 2) specifies this behaviour for `vector::resize`

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

if ( sz > size ())
  insert ( end () , sz - size () , c );
else if ( sz < size ())
  erase ( begin ()+ sz , end ());
else
; // Does nothing

So yes, the vector ignores it and you don't need to perform a check on your own.

Problem

I can't find this piece of information. I'm dealing with an odd situation here where i'm inside of a loop and i can get a random information at any given time. This information has to be stored in a vector. Now each frame i have to set this vector to ensure that i won't exeed the space (i'm writing values into random points in the vector using indexing). Now assuming there's no way to change this piece of code, i want to know, does the vector "ignore" the resize() function if i send an argument that's exactly the size of the vector? Where can i find this information?

Original source