Internet Cocaine

> what is abstract data type??can anyone provide me two examples please??

An abstract data type is like a normal data type, say int or char, but one that was originally only intended to compile on Abstract C, an implementation of C by K&R that built upon the C89 standard, and added support for ADTs and abstract constants (off-topic, quite an advanced subject). Many other languages have added implementations of this feature, which is why for example you’ll hear of Java developers and C++ developers talking of ADTs.
Two examples of ADTs are:
1. abs_int - an abstract definition of the integer type, which can also store dates in native system format, and floating point values of up to 20 significant digits.
2. linked lists - these are abstract data types that have been implemented in almost every modern language.  Note that they originated in Abstract C (a sore point with Abstract C developers), and were rapidly adopted by other languages.