Introduction to Programming End Show Resource Team R

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Introduction to Programming End Show

Introduction to Programming End Show

Resource Team R. P Ranjan-Lecturer, SPICTEC, Galle. W. M. A. S. Wijesekara-Centre manager, CRC

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

What is a computer program? n A computer program is a set of instructions

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

Cont…. n The machine can understand only the machine language. n Assembly and other

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

Classification of Programming Languages 1 st Generation Low Level Language Computer Language 2 nd

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

Generation of programming languages n 1 st Generation language ( 1 GL ) n

Generation of programming languages n 1 st Generation language ( 1 GL ) n 2 nd Generation languages( 2 GL ) n 3 rd Generation languages ( 3 GL ) n 4 th Generation languages ( 4 GL ) n 5 th Generation languages ( 5 GL ) End Show

1 st Generation language ( 1 GL ) n Machine level programming language n

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

2 nd Generation languages( 2 GL ) n Assembly language is used n Assembler

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

3 rd Generation languages ( 3 GL ) n It is easy to understand,

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

3 rd Generation languages ( 3 GL ) n many of the third generation

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

4 th Generation languages ( 4 GL ) n Introduced in the late 1980

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

5 th Generation languages ( 5 GL ) n Introduced in the early 1990

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

Low Level Languages n First and second generation languages are considered low level languages.

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

High Level Languages n 3 GL, 4 GL and 5 GL are considered high

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

Translators Translator is used to convert source code into object code. these are of

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

Assembler n is a low-level language Translator. n is a software program that converts

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

Interpreter n is a translator that goes through the process of translation every time

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

Compiler n is a translator of high level languages n converts a whole program

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