Pascal - Tutorialspoint

Pascali

PascalAbout the TutorialPascal is a procedural programming language, designed in 1968 and published in1970 by Niklaus Wirth and named in honor of the French mathematician andphilosopher Blaise Pascal. Pascal runs on a variety of platforms, such as Windows,Mac OS, and various versions of UNIX/Linux.This tutorial will give you great understanding of Pascal to proceed with Delphiand other related frameworks etc.AudienceThis tutorial is designed for Software Professionals who are willing to learn PascalProgramming Language in simple and easy steps. This tutorial will give you greatunderstanding on Pascal Programming concepts, and after completing this tutorial,you will be at intermediate level of expertise from where you can take yourself tohigher level of expertise.PrerequisitesBefore proceeding with this tutorial you should have a basic understanding ofsoftware basic concepts like what is source code, compiler, text editor, andexecution of programs, etc. If you already have understanding on any othercomputer programming language, then it will be an added advantage to proceed.Copyright & Disclaimer Copyright 2015 by Tutorials Point (I) Pvt. Ltd.All the content and graphics published in this e-book are the property of TutorialsPoint (I) Pvt. Ltd. The user of this e-book can retain a copy for future referencebut commercial use of this data is not allowed. Distribution or republishing anycontent or a part of the content of this e-book in any manner is also not allowedwithout written consent of the publisher.We strive to update the contents of our website and tutorials as timely and asprecisely as possible, however, the contents may contain inaccuracies or errors.Tutorials Point (I) Pvt. Ltd. provides no guarantee regarding the accuracy,timeliness or completeness of our website or its contents including this tutorial. Ifyou discover any errors on our website or in this tutorial, please notify us atcontact@tutorialspoint.comii

PascalTable of ContentsAbout the Tutorial . iiAudience . iiPrerequisites . iiCopyright & Disclaimer. iiTable of Contents . i1.OVERVIEW. 1Features of the Pascal Language . 1Facts about Pascal . 1Why to use Pascal?. 22.ENVIRONMENT SET UP . 3Installing Free Pascal on Linux . 3Installing Free Pascal on Mac . 4Installing Free Pascal on Windows . 4Text Editor. 43.PROGRAM STRUCTURE. 5Pascal Program Structure . 5Pascal Hello World Example . 6Compile and Execute Pascal Program . 74.BASIC SYNTAX . 9Variable. 9Functions/Procedures . 9Comments . 9Case Sensitivity . 10Pascal Statements . 10i

PascalReserved Words in Pascal . 10Character Set and Identifiers in Pascal . 105.DATA TYPES . 12Pascal Data Types . 12Type Declarations. 12Integer Types . 13Constants . 13Enumerated types . 14Subrange Types . 146.VARIABLE TYPES . 16Basic Variables in Pascal . 16Variable Declaration in Pascal . 16Variable Initialization in Pascal . 18Enumerated Variables . 19Subrange Variables . 207.CONSTANTS . 21Declaring Constants . 218.OPERATORS . 23Arithmetic Operators . 23Relational Operators . 24Boolean Operators . 26Bit Operators. 28Operators Precedence in Pascal . 319.DECISION MAKING. 33if-then Statement . 34Syntax . 34ii

PascalFlow Diagram . 35Example . 35if-then-else Statement . 36Syntax . 36Flow Diagram . 36Example . 37The if-then-else if-then-else Statement . 37Syntax . 38Example . 38Nested if-then Statements . 39Syntax . 39Example . 40Case Statement . 41Syntax . 41Flow Diagram . 42Example . 42Case Else Statement . 43Syntax . 43Flow Diagram . 44Example . 44Nested Case Statements . 45Syntax . 45Example . 4510. LOOPS . 47While-do Loops . 48Syntax . 48Flow Diagram . 49iii

PascalExample . 49For-do Loop . 50Syntax . 50Example . 51Repeat-Until Loop . 52Syntax . 52Flow Diagram . 53Example . 53Nested Loops . 54Example . 55Loop Control Statements: . 56Break Statement . 56Syntax . 57Flow Diagram: . 57Example . 57Continue Statement . 58Syntax . 58Flow Diagram . 59Example . 59goto Statement . 60Syntax . 60Flow Diagram . 61Example . 6111. FUNCTIONS . 63Subprograms . 63Functions . 63Defining a Function . 63iv

PascalFunction Declarations . 65Calling a Function . 6512. PROCEDURES. 67Defining a Procedure . 67Procedure Declarations . 68Calling a Procedure . 68Recursive Subprograms . 69Arguments of a Subprogram: . 71Subprogram Call by Value . 71Subprogram Call by Reference . 7313. VARIABLE SCOPE . 75Local Variables . 75Global Variables . 76v

1. OVERVIEWPascalPascal is a general-purpose, high-level language that was originally developed byNiklaus Wirth in the early 1970s. It was developed for teaching programming as asystematic discipline and to develop reliable and efficient programs.Pascal is Algol-based language and includes many constructs of Algol. Algol 60 is asubset of Pascal. Pascal offers several data types and programming structures. It iseasy to understand and maintain the Pascal programs.Pascal has grown in popularity in th

Free Pascal: it is a free compiler for running Pascal and Object Pascal programs. Free Pascal compiler is a 32- and 64-bit Turbo Pascal and Delphi compatible Pascal compiler for Linux, Windows, OS/2, FreeBSD, Mac OS X, DOS, and several other platforms. Turbo51: it is a free Pascal