Iterator

An iterator is like a pointer.( In fact, pointers are one kind of STL iterator.) Like a pointer, an pointer can refer to an element of a sequence, can be dereferenced to get the value of the object to which it refers, and can be manipulated like a pointer to refer to different elements of a sequence. STL iterator may be predefined pointers, or they may be user-defined class types that overload the appropriate operators to have the same syntax of use as a predefined pointer(see Smart Pointer).