Thread: question about vector

If you're that concerned about memory, then you'd be better off using an array and resizing it yourself. The STL with its heaping amounts of usefullness and ease comes with overhead.

vectors are destroyed as soon as they go out of scope. If you want to make sure a vector is destroyed at some point, put it in a block of code so that it'll be destroyed as soon as you're done with it.

When you clear() or delete[] memory, you're not erasing something like you would penciled remarks on paper. Your computer doesn't get out it's eraser and rub out what's in that memory. What's really going on is that that memory is being freed. That means that if anybody else needs it, it's there. But until it's used by anyone else, it just sits there with whatever used to be in there.

As someone else said, referencing freed memory is undefined. What you did was free up some memory and then take a look at what was there. Chances are good that that memory wasn't yet used by another process, so it's still sitting there. That doesn't mean you should be using it, however, because if another process needs some memory and overwrites that area of memory, then when you try to access it next, you'll get garbage.

Yes, that's exactly what it means. Also, the memory is in an undefined state at computer startup to begin with.