Iterator encapsulates an array and providing functions similar to the ones that exist in the vector class in C .Vectors are arrays of values that may have mixed data types. Each value of a vector is accessed by the respective numerical index position.Iterator provides many functions to access vector arrays manipulating their values and indexes.

data structure is a PHP implementation of several Java classes for manipulating common data types.Currently data structure provides ports of the classes: String, StringBuffer, StringTokenizer and Vector.