Friday, December 13, 2019

Introduction to Programming language



  • A language that is acceptable by the computer system is called a computer language or programming language.It is a medium of communication between the computer & user.
  • A programming language is composed of a set of instruction i.e. understandable to the programmer and recognizable by a computer.The way of writing instruction in such a language is called programming or coding.
  • All computer language can be broadly classified into the following three main categories i.e.
            (a). Machine Level Language
            (b). Assembly Level Language
            (c). High Level Language

A.Machine Level Language:

- This is a sequence of instruction written in binary numbers consisting of 1's & 0's, which is computer can understand directly. Hence this is called as the computer's own language.
- This is a low level language and is consider to be the 1st generation language(1GL).

Advantages

  • It is faster in execution since the computer directly start executive it.
  • It is machine independent.
  • It is difficult to write a program in machine level language.
  • programmer feels very difficult to remember the opcode and to keep the track of the storage location of data and instruction so programming errors are found.
  • It is very difficult to modify the program written in this language.
- To over come these difficulties assembly language developed which is easier then machine level language and easy to perform a task.

B.Assembly Level Language:

- When symbols such as letters ,digits or special character are employed for the operation,operand and other representation is called the assembly language program.
- Such representation are use instead of binary code. As the program written with such codes forms an assembly language program.
- This is consider to be a 2nd generation language(2GL).
- Machine & Assembly language are refereed to as low-level languages.Since the codding for a problem is at the individual instruction level.
- Each computer has its own assembly language that is depend upon the internal architecture processor.
- An assembler is a translator  that text input in the form of the assembly language program and produces machine language code as it's output. 
- An assembly language program cannot be executed by a machine directly as it is not in a binary machine language form.
- An assembler is needed to translate an assembly language program in to the object code which can be executed by the machine. 

Advantages

  • It is easier to understand and convenient for user due to the use of symbols.
  • It is easier locate and correct error and easier to modify.
  • Here the programmer not worried above the storage location of the data.
Disadvantages
  • It is specific to particular machine architecture.
  • since assembly language is machine dependent and assembly language programmer must have knowledge of hardware.
  • It is not portable in nature.
Again it creates a difficulty for performed certain task, to handle such problem high level language was developed.

C.High Level Language:

- High level languages were designed to overcome the limitations of the low level programming languages.
- COBOL,FORTRAN and BASIC are some of the example of high level programming languages.
- High level language are also called 3rd generation language(3GL).
- Since a high level source program must be translated first into the form which is machine can understand this is done by software called compiler.
- Compiler text the source called as input and produces the machine understandable code of the machine as output on which it is to be executed.

Advantages

  • Readability:- Program written in these languages are more readable than these written in assembly and machine language.
  • Portability:- High level programming language can be run on different machines with little or no change.
  • Easy debugging:- Errors can be easily detected and removable.
  • Easy in the development of software:- Since the commands of these programming languages are closer to the English language software can be developed easily by using such programming languages.
Disadvantages
  • Less flexibility:- These languages are less flexible then assembly languages because they don't normally have instructions or mechanism to control the computers,CPU,memory & register.
  • Lower efficiency:- It has lower efficiency then one written in assembly languages or machine languages then we have fourth generation languages.

Fourth generation languages(4GL):

- Fourth generation language are not as clearly defined as other earlier generation. Most people feel that a 4GL as a high level languages that requires significantly fewer instruction to accomplish a particular task that a 3GL done.
- Thus a programmer should be able to write a program faster then in 3rd generation language.
Advantages
  • System development is faster.
  • It is easy to maintain the program.
  • End users can offend can developed their own applications.
  • Program productivity enhanced.

Fifth generation language(5GL):

- In fifth generation programming language natural language plays a vital role.
- It is very much similar to query languages.
- The text of a natural language statement resembles human speech closely.

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