Why doesn't vector::clear remove elements from a vector?

Question

When I use clear() on a std::vector, it is supposed to destroy all the elements in the vector, but instead it doesn\'t.

Sample

Answer 1

The operator[] is efficient but comes at a price: it does not perform boundary checking.

There are safer yet efficient way to access a vector, like iterators and so on.

If you need a vector for random access (i.e. not always sequential), either be very careful on how you write your programs, or use the less efficient at(), which in the same conditions would have thrown an exception.