Programming Language

Programming Language:

• A programming Language is a notational system intended primarily to facilitate human-machine interaction.
• The notational is understood both by human and machine.
• The programming language has Syntax, and language elements have Semantics.

What is a program?

• A program is something that is produced using a programming Language.
• A program is a structured entity with Semantics.

What is programming?

What is programming?

• Programming is a Science:

Because it implement the algorithms describe by mathematics and science.

• Programming is a Skill:

Because it requires design efforts.

• Programming is an Engineering:

Because it requires a tradeoffs between program size, speed, time (required for development and debugging) and maintainability among many solutions.

• Programming is an Art

It requires creativity and employ imagination.

Types of programming Languages

Levels/Generations of Programming Languages

• 1st Generation Programming language (1GL)
• Machine Language: 0s or 1s
• 2nd Generation Programming language (2GL)
• Assembly Language : Mnemonics
• 3rd Generation Programming language (3GL)
• High-Level Languages ; (procedure oriented or Object Oriented)
• 4th Generation Programming language (4GL)
• Very-High-Level Languages
• 5th Generation Programming Language
• Natural Languages

Machine language  (1GL)

• The lowest level of language.
• The language used to program the first-generation computers.
• The instructions in 1GL are made of binary numbers, represented by 1s and 0s.
• 1s and 0s correspond to the on and off states of electrical switches.
• Suitable for the understanding of the machine but very much difficult to interpret and learn by the human programmer.

Assembly language (2GL)

• Low-level language that allows a programmer to use abbreviations or easily remembered words instead of numbers.
• These Observations are called Mnemonics. These Mnemonic are Opcode and Operands

For Example:   ADD  AX, BX

MOV  CX, AX

INC  CX

Op-code;  ADD, MOV, INC

Operands  AX, BX,CX

Assembly language (2GL)

• Programmer can write instructions faster but it is still not an easy language to learn.
• Drawback: The language is specific to a particular processor family and environment. (Machine Dependent Language)
• Assembler – A program that translates the assembly language program into machine language.

High Level languages (3GL)

• A High-Level Language is an English-like language.
• It is a refinement of a second-generation programming language.
• It allowed users to write in familiar notation, rather than numbers or abbreviations.
• Most High-level languages are not Machine Dependent.
• Translator for High-level languages is either a Compiler or an Interpreter.
• Examples of High-level languages:

―FORTRON

―COBOL

―BASIC

―C and C++

Very-High-Level Languages (4GL)

• 4GLs are much more user-oriented and allow programmers to develop programs with fewer commands compared with 3GLs.
• Non-Procedural Language; Programmers don’t have to specify all the programming logic, only tell the computer what they want done.
• Saves a lot of time.
• 4GLs consist of report generators, query languages, application generators, and interactive database management system
• For example:
• RPG III (Report Generator)
• SQL (Structured Query Language)
• NOMAD and FOCUS (DBMS)

Natural Languages (5GL)

• Two types
• Ordinary Human Languages; like English.
• Programming language that use human language to give people a more natural connection with computers.
• 5GLs are designed to make the computer solve a given problem without the programmer.
• Natural languages are part of the field of study known as Artificial Intelligence.
• Develop machines to emulate human-like qualities such as learning, reasoning, communicating, seeing and hearing.

Evolution of Programming

Programming Paradigms

A number of programming paradigms are:

• Procedural/Imperative Programming
• Functional Programming
• Declarative Programming
• Object Oriented Programming
• Event driven Programming
• Parallel Programming

Procedural or Imperative

• Imperative programs emphasize “tell what to do”
• When we say “ Do this, then do this, then do this, and if xx, do this, otherwise do this” This is imperative programming:
• They focus on evaluating expressions and storing results in a variable.
• The most common imperative language consists of statements such as:

a = 10;

b = 5;

c = a + b;

Example of imperative  languages are:

• Assembly language
• COBOL
• Pascal
• C and C++

    Is there any Best Programming Language?

• Programming Language is probably used most efficient if it is well suited For a specific task.
• For example
• Business applications are often written in COBOL.
• Beginners to programming use BASIC.
• Scientific programming is often undertaken with either FORTON, PASCAL or C.

Language Evaluation Criteria

• Readability: measure programmer ease in reading source       code
• Orthogonality: include context sensitive restrictions.
• Applicability: this is best suited as “use the right tool for the      job”
• Writ ability: includes simplicity and orthogonality and      support for the abstraction
• Reliability: include type checking and inspection handling
• Cost: includes learning and writing cost, productivity,      compilation cost, execution cost, debugging        cost etc.
• Other: flexibility of control statements and availability      of data structures

History of C Language

• A general-purpose computer programming language.
• Developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the UNIX operating system.
• Descendant of Ken Thompson’s language “B”
• The first C programming language standard was published in 1978 as “The C Programming Language” by Kernighan and Ritchie (K&R).
• “ANSI C” was the second C programming language standard published in 1989.
• ISO approved “ANSI C” in 1990.
• The latest stable release is C11.