Sorting (asymptotic) complexity problem
I have some problems with "asymptotic notations". I have already learned the thery about that but there is still something unclear for me "in practice".
Let me show you some simple example:
Let's say we have the "Selection" sorting algorithm. The fact is it has the time complexity of "O(n^2) (squared)". But what does it exactly mean?
Does it mean that at worst case this algorithm makes n^2 comparisons or n^2 selections or n^2 assignments or n^2 "something else"?
In other words, how can I simply and logically find out the complexity of some algorithm?