data type is type together with collection of operations to manipulate the type for examplean integer variable is member of the integer data type addition is an example of an operation on the integer data type distinction should be made between the logical concept of data type and its physical implementation in computer program for examplethere are two traditional implementations for the list data typethe linked list and the array-based list the list data type can therefore be implemented using linked list or an array even the term "arrayis ambiguous in that it can refer either to data type or an implementation "arrayis commonly used in computer programming to mean contiguous block of memory locationswhere each memory location stores one fixed-length data item by this meaningan array is physical data structure howeverarray can also mean logical data type composed of (typically homogeneouscollection of data itemswith each data item identified by an index number it is possible to implement arrays in many different ways for examplesection describes the data structure used to implement sparse matrixa large two-dimensional array that stores only relatively few non-zero values this implementation is quite different from the physical representation of an array as contiguous memory locations an abstract data type (adtis the realization of data type as software component the interface of the adt is defined in terms of type and set of operations on that type the behavior of each operation is determined by its inputs and outputs an adt does not specify how the data type is implemented these implementation details are hidden from the user of the adt and protected from outside accessa concept referred to as encapsulation data structure is the implementation for an adt in an object-oriented language such as javaan adt and its implementation together make up class each operation associated with the adt is implemented by member function or method the variables that define the space required by data item are referred to as data members an object is an instance of classthat issomething that is created and takes up storage during the execution of computer program the term "data structureoften refers to data stored in computer' main memory the related term file structure often refers to the organization of data on peripheral storagesuch as disk drive or cd-rom example the mathematical concept of an integeralong with operations that manipulate integersform data type the java int variable type is physical representation of the abstract integer the int variable typealong with the operations that act on an int variableform an adt un