The Language that computer can understand and execute it to perform a task is called programming language or computer language. The process of writing the instructions in a computer language is called programming or coding.
Types of programming language:
(1). Low level language:
(a). Machine language: In this language, the instructions are written in a sequence of numbers (0 and 1) to execute a task.
(b). Assembly language: A program written in assembly language needs to be converted into machine language to execute any task. There is a special program named Assembler that converts the assembly language into machine language.
(2). High Level language: In this language, the instructions are written in alphabets, numbers, and special characters. A program written in a high level language is called a source program.
Example: COBOL, PASCAL, C++, JAVA, BASIC, etc.
(3). Fourth Generation language: The fourth-generation language was developed in 1970 by an American Astronomer named Charles Moore. It is a non-procedural language which means it does not require to write a traditional program logic.
(4). Fifth Generation language: It is a problem-solving language using constraints given to the program. This language is used in the area of artificial intelligence.
Example: OPS5, Mercury, GPSS, LIPS, PROLOG, etc.
Open source software: This is a kind of software whose source code is available under a license for the users to use the software, make changes, and to redistribute it in modified form.
Example: Linux, Netscape, Apache, Open office, GIMP, etc.
Proprietary software: This is a kind of software with restrictions on using it, modifying it, and can not be distributed in modified form.
Example: CAD, Adobe Flash Player, Google Earth, Skype, etc.