Study Materials For Bank's Examinations

Professional Knowledge for Specialist Officer - Information Technology

Data Structure

In computer science, a data structure is a particular way of storing and organizing data in a computer so that it can be used efficiently.

Different kinds of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks. For example, B-trees are particularly well-suited for implementation of databases, while compiler implementations usually use hash tables to look up identifiers.

Data structures provide a means to manage large amounts of data efficiently, such as large databases and internet indexing services. Usually, efficient data structures are a key to designing efficient algorithms. Some formal design methods and programming languages emphasize data structures, rather than algorithms, as the key organizing factor in software design. Storing and retrieving can be carried out on data stored in both main memory and in secondary memory.

Language Support

Most assembly languages and some low-level languages, such as BCPL (Basic Combined Programming Language), lack support for data structures. Many high-level programming languages and some higher-level assembly languages, such as MASM, on the other hand, have special syntax or other built-in support for certain data structures, such as vectors (one-dimensional arrays) in the C language or multi-dimensional arrays in Pascal.

Most programming languages feature some sort of library mechanism that allows data structure implementations to be reused by different programs. Modern languages usually come with standard libraries that implement the most common data structures. Examples are the C++ Standard Template Library, the Java Collections Framework, and Microsoft’s .NET Framework.

Modern languages also generally support modular programming, the separation between the interface of a library module and its implementation. Some provide opaque data types that allow clients to hide implementation details. Object-oriented programming languages, such as C++, Java and Smalltalk may use classes for this purpose.

Many known data structures have concurrent versions that allow multiple computing threads to access the data structure simultaneously.

Data Type

In computer science and computer programming, a data type or simply type is a classification identifying one of various types of data, such as real-valued, integer or Boolean, that determines the possible values for that type; the operations that can be done on values of that type; the meaning of the data; and the way values of that type can be stored.

Overview

Data types are used within type systems, which offer various ways of defining, implementing and using them. Different type systems ensure varying degrees of type safety. Formally, a type can be defined as “any property of a programme we can determine without executing the program”.

Almost all programming languages explicitly include the notion of data type, though different languages may use different terminology. Common data types may include:

• Integers,

• Booleans,

• Characters,

• Floating-point numbers,

• Alphanumeric strings.

For example, in the Java programming language, the “int” type represents the set of 32-bit integers ranging in value from -2,147,483,648 to 2,147,483,647, as well as the operations that can be performed on integers, such as addition, subtraction, and multiplication. Colors, on the other hand, are represented by three bytes denoting the amounts each of red, green, and blue, and one string representing that color’s name; allowable operations include addition and subtraction, but not multiplication.

Most programming languages also allow the programmer to define additional data types, usually by combining multiple elements of other types and defining the valid operations of the new data type. For example, a programmer might create a new data type named “complex number” that would include real and imaginary parts. A data type also represents a constraint placed upon the interpretation of data in a type system, describing representation, interpretation and structure of values or objects stored in computer memory. The type system uses data type information to check correctness of computer programs that access or manipulate the data.

Definition of a “type”

(Parnas, Shore & Weiss 1976) identified five definitions of a “type” that were used—sometimes implicitly—in the literature:

Syntactic: A type is a purely syntactic label associated with a variable when it is declared. Such definitions of “type” do not give any semantic meaning to types.

Representation: A type is defined in terms of its composition of more primitive types—often machine types.

Representation and behaviour: A type is defined as its representation and a set of operators manipulating these representations.

Value space: A type is a set of possible values which a variable can possess. Such definitions make it possible to speak about (disjoint) unions or Cartesian products of types.

Value space and behaviour: A type is a set of values which a variable can possess and a set of functions that one can apply to these values.

The definition in terms of a representation was often done in imperative languages such as ALGOL and Pascal, while the definition in terms of a value space and behaviour was used in higher-level languages such as Simula and CLU.

Classes of Data Types

Boolean Type

Numeric Types

Composite Types

Enumerations

String and text types

Other Types

• Pointers and References

• Function Types

• Utility Types

• Type Systems

C++ Language

C++ (pronounced see plus plus) is a programming language that is general purpose, statically typed, free-form, multi-paradigm and compiled. It is regarded as an intermediate-level language, as it comprises both high-level and low-level language features.

Bjarne Stroustrup starting in 1979 at Bell Labs, C++ was originally named C with Classes, adding object oriented features, such as classes, and other enhancements to the C programming language. The language was renamed C++ in 1983.

C++ is one of the most popular programming languages variety of hardware and operating system platforms. As an efficient compiler to native code, its application domains include systems software, application software, device drivers, embedded software, high-performance server and client applications, and entertainment software such as video games.

Including the GNU Project, LLVM, Microsoft and Intel. C++ has greatly influenced many other popular programming languages, most notably C#.

The language began as enhancements to C, first adding classes, then virtual functions, operator overloading, multiple inheritance, templates and exception handling, among other features.

After years of development, the C++ programming language standard was ratified in 1998 as ISO/IEC 14882:1998. The standard was amended by the 2003 technical corrigendum, ISO/IEC 14882:2003. The current standard extending C++ with new features was ratified and published by ISO in September 2011 as ISO/IEC 14882:2011 (informally known as C++11).

Developed by as a pun involving the increment operator and is implemented on a wide

Several groups provide both free and proprietary C++ compiler software, and Java.

History

Bjarne Stroustrup, creator of C++

Bjarne Stroustrup, a Danish and British trained computer scientist, began his work on “C with Classes” in 1979.

In programming for his Ph.D. thesis. Stroustrup found that Simula had features that were very helpful for large software development, but the language was too slow for practical use, while BCPL was fast but too low-level to be suitable for large software development. When Stroustrup started working in AT&T Bell Labs, he had the problem of analyzing the UNIX kernel with respect to distributed computing. Remembering his Ph.D. experience, Stroustrup set out to enhance the C language with Simula-like features.

General-purpose, fast, portable and widely used. Besides C and Simula, some other languages that inspired him were ALGOL 68, Ada, CLU and ML. At first, the class, derived class, strong typing, inlining, and default argument features were added to C via Stroustrup’s “C with Classes”

The idea of creating a new language originated from Stroustrup’s experience C was chosen because it was to C compiler, C pre.

In 1983, the name of the language was changed from C with Classes to C++ (++ being the increment operator in C). New features were added including virtual functions, function name and operator overloading, references, constants, user-controlled free-store memory control, improved type checking, and BCPL style single-line comments with two forward slashes (//), as well as the development of a proper compiler for C++, C front. In 1985, the first edition of The C++ Programming Language was released, providing an important reference to the language, as there was not yet an official standard.

Released in October of the same year second edition of The C++ Programming Language was released in 1991, included multiple inheritance, abstract classes, static member functions, const member functions, and protected members. In 1990, The Annotated C++ Reference Manual was published. This work became the basis for the future standard. Late feature additions included templates, exceptions, namespaces, new casts, and a Boolean type.

As the C++ language evolved, the standard library evolved with it. The first addition to the C++ standard library was the stream I/O library which provided facilities to replace the traditional C functions such as printf and scanf. Later, among the most significant additions to the standard library, was a large amount of the Standard Template Library.

It is possible to write object oriented or procedural code in the same program in C++. This has caused some concern that some C++ programmers are still writing procedural code, but are under the impression that it is object oriented, simply because they are using C++. Often it is an amalgamation of the two. This usually causes most problems when the code is revisited or the task is taken over by another coder.

C++ continues to be used and is one of the preferred programming languages to develop professional applications.

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