data structures using many timetwo or more operations are applied simultaneously in given situation for exampleif we want to delete the details of student whose name is xthen we first have to search the list of students to find whether the record of exists or not and if it exists then at which locationso that the details can be deleted from that particular location abstract data type an abstract data type (adtis the way we look at data structurefocusing on what it does and ignoring how it does its job for examplestacks and queues are perfect examples of an adt we can implement both these adts using an array or linked list this demonstrates the 'abstractnature of stacks and queues to further understand the meaning of an abstract data typewe will break the term into 'data typeand 'abstract'and then discuss their meanings data type data type of variable is the set of values that the variable can take we have already read the basic data types in include intcharfloatand double when we talk about primitive type (built-in data type)we actually consider two thingsa data item with certain characteristics and the permissible operations on that data for examplean int variable can contain any whole-number value from - to and can be operated with the operators +-*and in other wordsthe operations that can be performed on data type are an inseparable part of its identity thereforewhen we declare variable of an abstract data type ( stack or queue)we also need to specify the operations that can be performed on it abstract the word 'abstractin the context of data structures means considered apart from the detailed specifications or implementation in can abstract data type can be structure considered without regard to its implementation it can be thought of as 'descriptionof the data in the structure with list of operations that can be performed on the data within that structure the end-user is not concerned about the details of how the methods carry out their tasks they are only aware of the methods that are available to them and are only concerned about calling those methods and getting the results they are not concerned about how they work for examplewhen we use stack or queuethe user is concerned only with the type of data and the operations that can be performed on it thereforethe fundamentals of how the data is stored should be invisible to the user they should not be concerned with how the methods work or what structures are being used to store the data they should just know that to work with stacksthey have push(and pop(functions available to them using these functionsthey can manipulate the data (insertion or deletionstored in the stack advantage of using adts in the real worldprograms evolve as result of new requirements or constraintsso modification to program commonly requires change in one or more of its data structures for exampleif you want to add new field to student' record to keep track of more information about each studentthen it will be better to replace an array with linked structure to improve the program' efficiency in such scenariorewriting every procedure that uses the changed structure is not desirable thereforea better alternative is to separate the use of data structure from the details of its implementation this is the principle underlying the use of abstract data types algorithms the typical definition of algorithm is ' formally defined procedure for performing some calculationif procedure is formally definedthen it can be implemented using formal language