Need of language (Computer oriented):

What is computer?

Computer is a programmable machine made with number of electrical, electronic and mechanical parts.

Computer is used to perform procedural arithmetic, relational and logical operations.

Computer is also used to control other machines and to store the data permanently for future usage.

The language of computers:

The field of computer sciences, which deals with the physical parts of computer, is called hardware. 

The natural language of computer hardware is the machine language (Binary code), which is difficult to learn and practice. 

Language:

The language is an interface among the programmer and computer hardware. 

Because machine language is difficult to learn and practice, there are number of other languages available to program the computer.

Programmers develop the software using any computer oriented language.

Where as users operate the computer using software.

 

Software:

Set of instructions developed in any computer oriented language is called a program.

Set of programs developed to solve any problem is called software.

Classification of languages:

Language is an interface among the programmer and computer hardware.

According the program development and execution efficiency languages are classified into low-level, high-level and middle level languages.

Low-level languages:

These are the languages developed and used before 60s.

These are the machine oriented languages which are difficult to learn and practice.

Prior knowledge in computer organization (technical knowledge) is needed to learn these languages.

These languages have low program development efficiency and high program execution efficiency (difficult to develop but effective in execution).

Examples:

Machine language

Assembly language (ALP).

High-level languages:

These are the programmer friendly languages. 

Simple English words, operators and expressions made the language easy to learn and practice.  

Any body from any field can learn these languages to develop software according to their requirement.

These languages have high program development efficiency and low program execution efficiency (Easy to develop but slow in execution).

Examples:

BASIC (Beginners All Purpose Symbolic Instruction Code). 

-Used to develop small applications.

COBOL (Common Business Oriented Language)

-Used to develop business applications

Pascal

-Used to develop scientific applications.

FORTRAN (Formula Translation)

Middle level languages:

According to the program development and execution efficiency, the performance of these languages is existed in between both the low-level and high-level languages.

Examples:

C, C++, Java etc.

 

Need of translator:

Natural language of computer hardware is the machine language. 

Computer can’t directly understand the source code written any high-level and middle-level languages. 

We need a translator to translate the source code into executable code. 

According to the functional nature these are of two types.

Interpreter

Compiler

Interpreter:

It is a translator, translates the source code into executable code, statement after statement in a procedural order.

The executable code generated by the interpreter is executed by the computer hardware.

Interpreter accepts the data from either the user or from other source while executing the program.

Need both the source code and interpreter every time we execute the program. 

Compiler:

It is a translator; translates the total source code into executable code at once.

The executable code generated by the compiler is used as an application (software).

We no more require either the source code or compiler once the, compiler produces the executable code.

Most of the languages like C, C++, and Pascal etc. use compiler.