1. Introduction to Programming End Show

2. Resource Team R.P Ranjan-Lecturer, SPICTEC, Galle. W.M.A.S. Wijesekara-Centre manager,CRC Hali-Ela H.P.U.S Indra Kumara-Instructor,CRC Hanguranketha R.M.P Bandara-Lecturer,CPICTEC Gurudeniya K.M.P.U Wimalaweera-Instructor,CRC Polonnaruwa End Show

3. What is a computer program? A computer program is a set of instructions or commands, which tell the computer what to do. A computer language is a set of symbols and rules used in constructing programs. Computer languages are used to develop application programs

4. End Show Cont…. The machine can understand only the machine language. Assembly and other high level languages are not machine language. To transform these languages into machine language, translators are needed. Source CodeObject Code Translator

5. Low Level Language High Level Language 1 st Generation 2 nd Generation 3 rd Generation 4 th Generation 5 th Generation Computer Language Classification of Programming Languages End Show

6. Generation of programming languages 1 st Generation language ( 1GL ) 2 nd Generation languages( 2GL ) 3 rd Generation languages ( 3GL ) 4 th Generation languages ( 4GL ) 5 th Generation languages ( 5GL )

7. End Show 1 st Generation language ( 1GL ) Machine level programming language Machine code is the binary digit language It consists of 1s and 0s. The machine can directly execute the machine code Execution is speedy because no translators are used. It is very difficult to write and modify programs. It is machine dependant, because machine-language instructions vary according to computer architecture. It is a low level language

8. End Show 2 nd Generation languages( 2GL ) Assembly language is used Assembler is used to convert assembly language to machine language Mnemonics and variables are used to write codes It is a machine dependant language Difficult to write and modify programs It is a low level language Execution is fast

9. End Show 3 rd Generation languages ( 3GL ) It is easy to understand, because it is similar to human languages Translators are used to convert high level language to machine language Compilers or interpreters are used as translators. Some of the 3 rd generation languages are unstructured languages such as Basic It is easy write and modify programs

10. End Show 3 rd Generation languages ( 3GL ) many of the third generation languages are procedural languages because the program instructions comprise a list of steps or procedures They are not machine dependent languages One instruction in a third generation language can replace many assembly language instructions programmer has to describe how it should be done. Ex : Basic, Fortran, Cobol, Pascal

11. End Show 4 th Generation languages ( 4GL ) Introduced in the late 1980s They are designed to reduce programming effort It consumes less time to write a program They are non procedural languages Very easy to write and modify One instruction in 4GL can replace a number of 3GL instructions Programmer has to describe what is to be done. 4GL languages reduce software development cost. They are described as application development without programmers Ex : FOCUS, IDEAL, dbase III plus

12. End Show 5 th Generation languages ( 5GL ) Introduced in the early 1990s User-friendly Graphical User Interfaces are facilitated. Very easy to write and modify program Execution speed is low Event driven programs were introduced Ex: Visual basic, Visual C++, Small Talk

13. End Show Low Level Languages First and second generation languages are considered low level languages. They are machine dependant languages These languages are close to the hardware The programmer should have hardware knowledge to write a program Productivity is low

14. End Show High Level Languages 3GL,4GL and 5GL are considered high level languages They are machine independent languages It is easy to write and modify The programmer does not need knowledge of hardware to write programs Productivity is high Consume less time to write programs 5GL allow user-friendly facilities Translators need to be used to convert to machine language

15. End Show Translators Translator is used to convert source code into object code. these are of three types 1. Assembler 2. Interpreter 3. Compiler Source Code Object Code Translator

16. End Show Assembler is a low-level language Translator. is a software program that converts assembly language into machine language. converts mnemonics into machine code

17. End Show Interpreter is a translator that goes through the process of translation every time the program is run. is found running some versions of BASIC, where it translates one line of the program at a time.

18. End Show Compiler is a translator of high level languages converts a whole program into machine language at once translates source code into Object Code. This Object code is used to execute whenever it is run Recompiling required if any changes of source code