A programming language is a formal language for communicating with a computer without the ambiguity of human languages. A programming language has to be executed by a computer or design of the language degenerates into a futile intellectual exercise.
All over the world, language is the source of communication among human beings. Different countries/regions have different languages. Similarly, in order to communicate with the computer user also needs to operate in a language that would be understood by the computer. For this purpose, different languages are developed for performing different types of work on the computer. Basically, languages are divided into two categories according to their interpretation.
- Low Level Languages.
- High Level Languages.
LOW LEVEL LANGUAGES
Low level computer languages are machine codes or close to it. Computer cannot understand instructions given in high level languages or in English. It can only understand and execute instructions given in the form of machine language i.e. language of 0 and 1.
There are two types of low level languages:
- Machine Language.
- Assembly Language.
a) Machine Language
It is the lowest and most elementary level of Programming language and was the first type of programming language to be developed. Machine Language is basically the only language which computer can understand. In fact, a manufacturer designs a computer to obey just one Language, its machine code, which is represented inside the computer by a string of binary digits (bits) 0 and 1. The symbol 0 stands for the absence of Electric pulse and 1 for the presence of an electric pulse. Since a computer is capable of recognizing electric signals, therefore, it understands machine Language.
Advantages of Machine Language
- It makes fast and efficient use of the computer.
- It requires no translator to translate the code i.e. directly understood by the computer.
Disadvantages of Machine Language
- All operation codes have to be remembered.
- All memory addresses have to be remembered.
- It is hard to amend or find errors in a program written in the machine language.
- These languages are machine dependent i.e. a particular machine language can be used on only one type of computer.
b) Assembly Language
It was developed to overcome some of the many inconveniences of machine language. This is another low level but a very important language in which operation codes and operands are given in the form of alphanumeric symbols instead of Os and 1s. These alphanumeric symbols will be known as mnemonic codes and can have maximum of up to 5 letter combination e.g. ADD for addition, SUB for subtraction, START, LABEL etc. Because of this, feature is also known as ‘Symbolic Programming Language’. This language is also very difficult and needs a lot of practice to master because very small English support is given to this language. The language mainly helps in compiler orientations. The instructions of the Assembly language will also be converted to machine codes by language translator to be executed by the computer.
Advantages of Assembly Language
- It is easier to understand and use compared to machine language.
- It is easy to locate and correct errors.
- It is modified easily.
Disadvantages of Assembly Language
- Like machine language, it is also machine dependent.
- Since it is machine dependent programmer should have the knowledge of the hardware.
HIGH LEVEL LANGUAGES
High level computer languages give formats close to English language and the purpose of developing high level languages is to enable people to write programs easily and in their own native language environment (English). High-level languages are basically symbolic languages that use English words and/or mathematical symbols rather than mnemonic codes. Each instruction in the high level language is translated into many machine language instructions thus showing one-to-many translation.
Types of High Level Languages
Many languages have been developed for achieving different variety of tasks, some are fairly specialized while others are quite for general purpose.
These are categorized according to their use as follows:
a) Algebraic Formula-Type Processing: These languages are oriented towards the computational procedures for solving mathematical and statistical problem. Examples are:
- BASIC (Beginners All Purpose Symbolic Instruction Code).
- FORTRAN (Formula Translation).
- PL/I (Programming Language, Version 1).
- ALGOL (Algorithmic Language).
- APL (A Programming Language).
Business Data Processing: These languages emphasize their capabilities for maintaining data processing procedures and files handling problems. Examples are:
- COBOL (Common Business Oriented Language).
- RPG (Report Program Generator).
b) String and List Processing: These are used for string manipulation including search for patterns, inserting and deleting characters.
- LISP (List Processing).
- Prolog (Program in Logic).
Object Oriented Programming Language: In OOP, the computer program is divided into objects. Examples are:
Visual programming language: These are designed for building Windows-based applications Examples are:
- Visual Basic.
- Visual Java.
- Visual C.
Advantages of High Level Language
The following are the advantages of a high level language:
- Similar to English with vocabulary of words and symbols.
- Therefore it is easier to learn.
- They require less time to write.
- They are easier to maintain.
- Problem oriented rather than ‘machine’ based.
- Program written in a high-level language can be translated into many machine language and therefore can run on any computer for which there exists an appropriate translator.
- It is independent of the machine on which it is used i.e. Programs developed in high level language can be run on any Computer.
Disadvantages of High Level Language
- A high-level language has to be translated into the machine language by a translator and thus a price in computer time is paid.
- The object code generated by a translator might be inefficient compared to an equivalent assembly language program.
FIVE GENERATIONS OF PROGRAMMING LANGUAGES
So far, 5 generations of programming languages have been defined. These ranges from machine level languages (1GL) to languages necessary for Artificial Intelligence and Neural Networks (5GL). A brief introduction of each of the five generations is given below:
A) First Generation Programming Language (1GL): First generation of programming language refers to machine language. Machine language is lower level language which uses object code (sometimes also known as machine code). Object code is the combination of binary digits. These languages directly talk to hardware.
B) Second Generation Programming Language (2GL): Second generation of languages is also low level language which is known as assembly language. Assembly languages are the interface between Machine level languages and High level languages.
C) Third Generation Programming Language (3GL): Third Generation programming languages are High level Programming languages like JAVA and C.
D) Fourth Generation Programming Language (4GL): This is the set of current generation programming languages. These languages are similar or closer to human languages.
General characteristics of 4GL are:
- Closer to human languages.
- Database supportive.
- Simple and requires less effort than 3GL.
- Non procedural.
Different types of 4 GL are:
- Query Generator.
- Report generator.
- Form Generator.
- Application Generator.
- GUI Generator.
- Relational Database Manager.
E) Fifth Generation Programming Language (5GL): Languages used for writing programs for Artificial Intelligence, Neural Network, Plasma Computing etc. come under 5GL. This is the future of programming language.