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TURBO-LESSONS A TURBO Pascal Tutorial Version 5.0 (for TURBO Pascal 5.0) by Dr. Lyle M. Faurot May 6, 1989 Copyright 1989 by Lyle M. Faurot. All Rights Reserved. î TURBO-LESSONS Registration Form Name____________________________________________ Date_____________ Street_____________________________________________________________ City________________________________ State_________ Zip____________ Would you like to receive notices about future releases of Tutorials and other products? Yes___ No___ [TP-5.0:R31] Where did you get your copy of TURBO-LESSONS?______________________ Your vote counts! Which of the following would you like next? _____ More TURBO-LESSONS for Turbo Pascal 5.0 (Several lessons of the next set are already in progress.) _____ TURBO-LESSONS for other programming languages Which ones? _______________________________________________ _____ TURBO-LESSONS for spreadsheets, word processors, other products Which ones? _______________________________________________ _______________________________________________ Comments, Suggestions: ------------------------------------------------------------------- ------------------------------------------------------------------- ------------------------------------------------------------------- ------------------------------------------------------------------- ------------------------------------------------------------------- =================================================================== TURBO-LESSONS for Turbo Pascal 5.0 Set 1: Lessons 1-16 $10.00 (U.S. Funds) Mail to: Dr. Lyle M. Faurot Box 494 Moorhead, MN 56560 î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 2 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TABLE OF CONTENTS INTRODUCTION........................................ 5 OBJECTIVES.......................................... 6 SHAREWARE NOTICE.................................... 7 What is SHAREWARE?.............................. 7 How is TUTORIAL Shareware Different?............ 7 Try Before You Buy.............................. 7 Why Register Your Copy of TURBO-LESSONS?........ 7 How to Register................................. 8 DISTRIBUTION OF TURBO-LESSONS....................... 9 Copying and Sharing TURBO-LESSONS............... 9 PC Clubs/Bulletin Boards........................ 9 PD/Shareware Disk Distribution Companies........ 9 TURBO-LESSON Files on the Distribution Diskette. 10 TURBO-LESSON 1. GETTING STARTED (Version 5.0)...... 11 How to Start and Stop Turbo..................... 11 How to Switch and Zoom Windows.................. 13 How to Edit a File.............................. 14 How to Save a File.............................. 14 How to Display a Directory of Files............. 15 How to Edit a Different File.................... 16 How to Recover a File Saved Earlier............. 17 TURBO-LESSON 2. ESSENTIAL EDITING SKILLS........... 19 Moving the Cursor............................... 19 Inserting and Replacing Text.................... 20 Deleting Text................................... 21 Experimenting On Your Own....................... 22 Saving and Retrieving Programs.................. 22 Re-Editing Each File............................ 23 Getting Up to Speed............................. 24 TURBO-LESSON 3. PROGRAM STRUCTURE.................. 25 Program structure............................... 25 How to Compile a Program........................ 26 How to Run a Program............................ 27 Write and WriteLn statements.................... 27 Comments - at the beginning of program.......... 30 Comments - at the end of a statement line....... 31 Comments - deactivate a section of code......... 31 î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 3 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TABLE OF CONTENTS (continued) TURBO-LESSON 4. DECLARATIONS, INPUT................ 32 The DECLARATIONS Part of a Program.............. 32 VAR Declaration................................. 32 Input Using the ReadLn Statement................ 33 DEBUG - Tracing Statements...................... 34 DEBUG - Watching Variables..................... 35 Integer Variables............................... 36 TURBO-LESSON 5. INTEGER EXPRESSIONS................ 37 Assignment Statements........................... 37 DEBUG - Removing Watch Variables............... 38 Integer Expressions............................. 38 Problems with Expressions....................... 41 TURBO-LESSON 6. CONDITIONAL PROCESSING............. 43 Selection Structures for Conditional Processing. 43 DEBUG - Goto Cursor............................ 43 IF Statement (Two-way Selection)................ 44 IF Statement (One-way Selection)................ 45 TURBO-LESSON 7. REPEAT STATEMENT................... 48 CHARacter Variables............................. 48 BOOLEAN Variables............................... 49 REPEAT Statement................................ 50 TURBO-LESSON 8. CASE STATEMENT..................... 52 Block Statement................................. 52 CASE Statement.................................. 55 TURBO-LESSON 9. FOR STATEMENT...................... 57 Controlling Field Width in Write Statements..... 57 FOR Statement................................... 58 TURBO-LESSON 10. WHILE STATEMENT................... 60 CONSTant Declaration............................ 60 WHILE Statement................................. 61 Delay Timing Loop............................... 63 TURBO-LESSON 11. INTRODUCTION TO FUNCTIONS......... 65 Pascal Subprograms.............................. 65 FUNCTION Declaration............................ 66 User-defined Function........................... 66 Providing Input to the FUNCTION................. 67 TURBO-LESSON 12. A FUNCTION TO DETECT ERRORS....... 72 Error Detection................................. 72 Using a Predefined Function..................... 73 Writing Your Own Function....................... 74 î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 4 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TABLE OF CONTENTS (continued) TURBO-LESSON 13. STRINGS........................... 76 Strings......................................... 76 String Replacement Statement.................... 76 Predefined String Function, LENGTH.............. 78 TURBO-LESSON 14. INTRODUCTION TO PROCEDURES........ 80 PROCEDURE Declaration........................... 80 Using a Procedure............................... 80 Using Parameters................................ 82 A Counter with Error Checking................... 83 TURBO-LESSON 15. INTERACTIVE SCREEN HANDLING....... 85 Setting up a Data Entry Screen.................. 85 Being Nice to Users - ClrScr.................... 86 Getting Around the Screen - GotoXY.............. 86 TURBO-LESSON 16. REAL NUMBERS...................... 88 Range of Real Numbers........................... 88 Input/Output of Real Numbers.................... 88 Calculations with Real Numbers.................. 89 Calculations with Integers and Real Numbers..... 91 A CHALLENGE......................................... 92 î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 5 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 INTRODUCTION Since TURBO-LESSONS were first made available as Shareware in 1985, Pascal programmers around the world have provided encouragement and some excellent suggestions for improving these lessons. I have used many of those suggestions in this update for Turbo Pascal 5.0. The new DEBUG feature in 5.0 adds a terrific learning tool. You will enjoy using the DEBUG "trace" and "watch" to explore the workings of this programming language. Each TURBO-LESSON is a bite-size tutorial which introduces one or more new concepts. Each of the lessons are presented in the same format which includes the OBJECTIVES of the lesson, and the TUTORIAL portion of the lesson. Most lessons direct you to work with a sample program which is provided with these lessons. Be sure you make a back-up copy of the programs - you will be modifying and adding to the sample programs, and may want to return to the original unmodified copy of a program. Sample programs are numbered to correspond to the lessons--for example, PROG3 goes with lesson 3. To begin, you should print the TURBO-LESSONS before loading TURBO. You may also want to print a copy of the programs. This will allow you to see the whole program. The screen window often limits your view to a small part of a program. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 6 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 OBJECTIVES The following objectives have guided the development of TURBO- LESSONS. 1. TO HELP BEGINNING PROGRAMMERS Programmers who had difficulty learning Pascal from reference books tell me they are able to make better progress on their own after completing TURBO-LESSONS. 2. TO HELP YOU GET STARTED PROGRAMMING IN PASCAL We hope to provide the basics you need to get started with Pascal and build your confidence and enthusiasm to continue learning on your own. 3. TO PROVIDE PRACTICAL PROGRAMMING TECHNIQUES There is more to programming than just learning the elements of the language. The programming techniques you learn will save you time and frustration in your future programming. 4. TO ENCOURAGE EXPERIMENTATION ON YOUR OWN Programming skill is acquired more by doing than by reading about it. The lessons are presented in a way designed to challenge you to try things on your own. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 7 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 SHAREWARE NOTICE What is SHAREWARE? SHAREWARE is a "Try Before You Buy" approach to marketing and distribution of products. Shareware is not free and it is not public domain. Shareware authors encourage users to copy and pass on their copyrighted products. If after trying out the product, you continue using it, payment is expected. How is TUTORIAL Shareware Different? Most Shareware products are successful if you evaluate the product and decide to continue using it. Just the opposite is true of Tutorial Shareware--it is successful if you don't need to continue using it. The value of a good tutorial is in the "FIRST USE". A successful tutorial is like a newspaper--use it once and discard it. (I hope you won't discard TURBO-LESSONS though. Give a copy to a friend.) Try Before You Buy Let me suggest the following way to "Try Before You Buy" in the special case of products which don't typically get "continued use." If you try the first few lessons and decide to continue, you are expected to pay for the lessons. If the tutorials are successful, you are "continuing to use" the skills and knowledge you received from the tutorials. Why Register Your Copy of TURBO-LESSONS? When you send your registration you: 1. Make it possible for the author to write more tutorials. 2. Help determine which tutorials will be written. 3. Find out about new products. The next set of TURBO-LESSONS for Turbo Pascal 5.0 is already under construction! These lessons will feature data structures--Arrays, Records, Files. 4. Support SHAREWARE marketing. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 8 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 How to Register The registration form is included with the first lesson file, TP-50A. The form is also stored in a file named REPLY. To print a copy of the form, type COPY REPLY PRN or COPY REPLY LPT1: When you complete the registration form, please include any comments about the lessons. This helps me improve the next version or correct errors. Please use U.S. funds in payment. It costs more than the price of TURBO-LESSONS to collect checks from other countries. CANADIAN checks are not a problem. My bank charges me $1.00 plus the exchange rate. If for some reason the file, REPLY, is not with the set of TURBO- LESSONS you receive, please let me know it is missing and where you obtained TURBO-LESSONS so I can correct the problem. You can mail your payment of $10.00 without the form to: Dr. Lyle M. Faurot Box 494 Moorhead, MN 56560 Thank you for supporting this product and the SHAREWARE marketing concept. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 9 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 DISTRIBUTION OF TURBO-LESSONS Copying and Sharing TURBO-LESSONS You are encouraged to copy and share these lessons with others. This is what makes shareware work--the author appreciates your help in distributing this product. TURBO-LESSONS may be freely copied and shared. TURBO-LESSONS may not be sold. PC Clubs and Disk Distribution companies may include TURBO-LESSONS in their disk offerings provided any price charged is based on the cost of disk and handling, and not on the contents of the disk. TURBO-LESSONS must be distributed complete with all files. A complete list of files appears later in this section. PC Clubs/Bulletin Boards TURBO-LESSONS may be distributed by PC Clubs and uploaded to Computer Bulletin Boards. The set must be distributed complete with all files provided. PD/Shareware Disk Distribution Companies Disk distribution companies may include TURBO-LESSONS in their offerings provided they represent TURBO-LESSONS as SHAREWARE, not Public Domain or Freeware. Also the complete set of lessons and files must be distributed together. Those who "buy" TURBO-LESSONS from disk companies should understand that the author receives no royalty of any kind from these sales. We are simply helping each other--I try to provide a quality product for them to distribute, they provide publicity and distribution which would otherwise be unavailable to me. Site Licensing Schools, companies and other organizations are encouraged to write for information about site licensing for multiple copies of TURBO- LESSONS. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 10 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TURBO-LESSON Files on the Distribution Diskette You should have received the following files with TURBO-LESSONS. The approximate number of pages is listed to help you print the lessons. File Contents Pages to Print TP-50A Lessons 1-2, Introduction, Table of Contents 25 TP-50B Lessons 3-6 23 TP-50C Lessons 7-11 24 TP-50D Lessons 12-16 21 REPLY Registration/Survey Form 1 README The starting point - read this first 1 PRINT.BAT To help you print the lessons PROGx.PAS These are the programs, numbered to correspond to the lessons. The following are included: PROG3.PAS, 4, 5, 6A, 6B, 6C, 7, 8, 9, 10, 11, 11A, 12, 12A, 13, 13A, 14, 14A, 15, 15A, 15B, 16, and TEST1.PAS. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 11 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TURBO-LESSON 1. GETTING STARTED (Version 5.0) OBJECTIVES - In lesson 1 you will learn how to: 1. Start and stop Turbo Pascal 2. Switch windows 3. Edit a file (programs are stored in files) 4. Save a file 5. Display a directory of files saved 6. Edit a different file 7. Recover a file saved earlier In lesson 1 you will learn to use the Turbo Pascal programming environment. Unlike many of the earlier programming language systems, Turbo provides the various tools needed in one package. This means you can quickly go from entering or correcting a program to running and testing the program. Turbo also speeds up debugging of the program by "pointing" to your error with the cursor, and indicating the nature of the problem. You will need the skills acquired in the first two lessons as you work through later lessons. If you find yourself unsure of some of these file skills later, be sure to come back to lessons 1 and 2 for help. 1. How to Start and Stop Turbo To get started, put a diskette with Turbo Pascal in your disk drive, or if you have Turbo Pascal on a hard disk, switch to the subdirectory with Turbo. The following files should be on the diskette or hard drive: Turbo.EXE, Turbo.TPL and Turbo.HLP. ##### DO: Type Turbo then press the Enter key to start Turbo Pascal. The screen which appears has the following across the top: File Edit Run Compile Options Debug Break/watch This is the main menu of Turbo Pascal. In this lesson you will explore only the first two options: File and Edit. Notice the first letter of each word is highlighted. You can choose any of the menu options by typing the first letter of the option while holding down the Alt key. If the first letter of each word doesn't appear highlighted, try adjusting the contrast and brightness controls of your computer monitor. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 12 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 To choose the File option, you would hold down the Alt key and type F. ##### DO: Type Alt-F (hold down the Alt key while you type F) to choose the File option. The window which appeared under File shows what you can do with files: Load a file, start a New file, Save a file, display a Directory of files saved, Quit Turbo Pascal, and several other choices. You have started Turbo--next you will need to know how to stop it. The Quit option lets you exit the Turbo programming environment. ##### DO: Type Q to leave Turbo. Try starting Turbo again and learn another way to use the menu. ##### DO: Type Turbo and press the Enter key to start Turbo. Notice the way one of the menu options is highlighted. ##### DO: Press the right arrow key several times. The highlight should move from one menu option to the next. Also try the left arrow. (If nothing happens, check for NUM at the lower right of the screen. If the word NUM appears, press the Num Lock Key--NUM will disappear. Now the arrow keys should work.) You chose the File option from the menu before by typing Alt-F. There's another way to choose an option--you can move the highlight to the option you want and press the Enter key. ##### DO: Move the highlight to the File option and press Enter. ##### DO: In the window of choices under File, use the down arrow key to move the highlight to Quit, then press Enter. NOTE: An option selected by typing the first letter is carried out immediately without pressing the Enter key. An option selected by moving the highlight to the desired option must be activated by pressing the Enter key. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 13 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 ##### DO: Try starting and stopping Turbo several times using both ways to choose File and Quit. 2. How to Switch and Zoom Windows There are two windows on the screen, the top one labelled Edit and the lower one Watch or Output. The Edit window is used for entering and editing programs. The Watch window is used with the DEBUG features in the lessons that follow. The Output window is used to display output when you run your programs. Switching the lower window between Watch and Output is covered in a later lesson. Only one of the two windows is active at any time. The active window has a double line at the top and the label is highlighted. ##### DO: Press F6 several times, noting the effect on the windows. F6 lets you switch between windows. Messages at the bottom of the screen show you the effect of special keys which are active with each window. ##### DO: Watch the messages at the bottom of the screen while you press F6 several times. Did you see how the F6 message changed? When the Edit screen is active, the message F6-Output tells you that pressing F6 will switch to the Output window. When the Output window is active, F6-Edit prompts you to press F6 to switch to the Edit window. The messages at the bottom of the screen will help you find your way around while you get acquainted with Turbo Pascal. One of the messages is F5-Zoom. F5 switches the active window between a full screen display and a partial screen display. Sometimes you want to see both windows, sometimes just one window expanded to fill the full screen. ##### DO: Press F5 several times. ##### DO: Use F6 to switch to the other window, then press F5 several times. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 14 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 This feature is handy when you would like the full screen for editing a program or when you want to see program output displayed on the full screen. To make it easier to see the features of the editor without the Output window, we will use the full screen Edit window to explore how to edit a file. 3. How to Edit a File Why do you need to know how to edit a file? Programs are stored in files. Before you can run a program you must type the program into a file. You also use the editor to correct mistakes in the program. You will learn more of the details of editing a file later. Here you will type a short sentence to be stored in the Editor Work file. Later you will use the editor to type in programs. NOTE: Editor Work file here refers to the file you are currently editing. Earlier versions of Turbo Pascal referred to this file as the Work file; Starting with version 4.0, this file is called the Editor file. I refer to this file as the Editor Work file throughout these lessons. ##### DO: If the Edit window is not the active one, use F6 to switch to it. Then use F5 to "Zoom" the Edit window to full screen size. (Remember, the active window is marked with a double line at the top.) The blinking cursor should be at the upper left corner of the edit window. ##### DO: Type the sentence: This is in a file named ONE. In the next section you will Save this file and in a later section Load it back into the Edit Work file again. 4. How to Save a File Why do you need to know how to save a file? When you edit a program, it is in the computer memory. When you turn the computer off or leave the Turbo Pascal programming environment you will lose the program in the computer's memory. To preserve the program for future use, you must save the program as a î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 15 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 file on diskette or hard disk. Saving a program means making a copy of the program which is currently in the Editor Work file and placing that copy on a disk. The Save choice in the File menu window is used to store the current Editor Work file on diskette or hard disk. ##### DO: Choose the File option (type Alt-F), type S to Save the file you just entered. Notice that you could use the arrow keys to move the highlight to Save instead of typing S. Remember to use the Enter key to activate the highlighted option. If you just type S no Enter is required. You will soon form the habit of using the menu technique you find best for you. Look at the status line at the top of the screen--the name of your file is NONAME.PAS. This is the name Turbo gives your file until you rename it something else. The first time you save your file you are reminded to rename it. ##### DO: At the rename prompt type ONE as the new name for your file. Press the Enter key. (If you already have a file named ONE.PAS on the disk, you will be prompted for permission to overwrite the old ONE.PAS.) NOTE: You could type ONE.PAS instead of ONE, but it's not necessary. PAS will be added as the file extension anytime you omit the extension. Your Editor Work file has been stored on the disk with a name of ONE.PAS. When you need to recover this file, you can get it back with the Load choice in the File menu window. You will do that in a bit, but first, let's see how to find out which files are on your disk. 5. How to Display a Directory of Files After you have saved a few files you may forget their names or forget which ones you have on your disk. The Directory choice in the File menu window helps you list your disk files. ##### DO: Get the File menu window and type D to display a directory. Did you get a directory? î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 16 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 First, Turbo gives you a choice. Do you want to list all files (*.*) or files with a file extension of PAS (*.PAS) or maybe files that start with the letter S (S*.*)? Please check your operating system manual if you need more help with the meaning of the asterisk (*) in selecting groups of files to display. Turbo suggests the choice, *.*, to display all files. ##### DO: At the Enter Mask prompt, *.*, press the Enter key. You should see a list of all your files on the screen. The Esc key is used to back up to a previous of the menu. While your directory is displayed you can return to the Directory choice in the File window by pressing the Esc key. ##### DO: Press Esc to back-up to the Directory choice. The F10 key provides another way to exit the directory display. Pressing F10 will take you back to the main menu. Both the directory display and the File window will disappear. ##### DO: Display the directory again. Then use F10 to return to the main menu. F10 will take you back to the main menu from almost anywhere in the Turbo programming environment. 6. How to Edit a Different File Under the File option, the New choice allows you to establish a new file. Since there can only be one Editor Work file in computer memory at one time, the current Editor Work file will be removed from memory before starting the new file. If you haven't saved the current Editor Work file since it was last changed, you will be prompted to save it before establishing a new Editor Work file. ##### DO: Choose New in the File menu window. If you are prompted to save the current file, type Y. The blinking cursor should be at the upper left of the edit window. This indicates the editor is ready to use. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 17 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 ##### DO: Type: This is in file TWO. ##### DO: Save the Editor Work file. Name it TWO. 7. How to Recover a File Saved Earlier You have two files saved on the disk: ONE.PAS and TWO.PAS. TWO.PAS is also in the Editor Work file. If you wanted to get ONE.PAS back for further editing you would use the Load choice in the File menu window. ##### DO: Get the File menu window and type L to load a file. Turbo prompts you for Load File Name. ##### DO: Type ONE and press Enter. Notice the name of the file in the status line at the top of the screen. It should be ONE.PAS. There's another way to select the file to load into the Editor Work file. This method allows you to select the desired file from a menu. Load the file named TWO.PAS again using the load menu. ##### DO: Get the File menu window and press L to Load a file. ##### DO: When the Load File Name prompt appears type *.PAS and press the Enter key. (*.PAS may already be in the prompt box. Then you would only need to press the Enter key.) All files with a PAS extension should be displayed. You can use the arrow keys to move the highlight to the file you want to load. When the desired file is highlighted, press the Enter key to load the file. ##### DO: Use the arrow keys to move the highlight to the file, TWO.PAS. Press the Enter key. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 18 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 Check the status line to verify that file TWO.PAS is in the Editor Work file. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 19 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 TURBO-LESSON 2. ESSENTIAL EDITING SKILLS OBJECTIVES - In lesson 2 you will develop skill in: 1. Moving the Cursor 2. Inserting and Replacing Text 3. Deleting Text 4. Efficiently Editing and Re-editing Files In the previous lesson you began your editing skills by entering a short sentence into a file and saving that file. In this lesson you will learn to get around the file by moving the cursor and to add, change, or delete text in the file. 1. Moving the Cursor To see how to move the cursor around you need several lines of text in your Editor Work file. Then you can try moving the cursor to see how the different keys work. NOTE: The Pascal programs supplied with these lessons are in files named PROG3.PAS, PROG4.PAS, etc. Sometimes you will need to create and name your own files for storing programs. I will simply suggest a file name to use when a DO section directs you to create a new file. In Turbo version 5.0 you don't supply the file name until the first time you save the file. I suggest you name the file immediately whether the version requires it or not, so that the file name always appears in the status line at the top of the Edit screen. You can save an "empty" file in 5.0 so you could save and name a file before editing it. ##### DO: Start a new file using the New option in the File menu box. ##### DO: Type the following lines into your Editor Work file. (Suggested file name: SKILLS.) This is not a program. This is only to seeee how teh editttor works. You can type whatever you want. Notice the status line on the top of the screen as you type. It lets you know the line and column of the cursor's position. To move around the screen easily, use the arrow keys at the right of the keyboard to move the cursor. If your keyboard doesn't have arrow keys, note that the following may be substituted for the arrow keys: î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 20 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 Ctrl-s = left-arrow Ctrl-d = right-arrow Ctrl-e = up-arrow Ctrl-x = down-arrow ##### DO: Try out the arrow keys. The left and right arrows move the cursor one character to the left or right, and the up and down arrows move the cursor one line up or down, as long as there is something typed there. ##### DO: To move a little faster, try Ctrl-left-arrow. It moves the cursor one word to the left. Ctrl-right-arrow moves one word to the right. (Ctrl-A = Ctrl-left-arrow, Ctrl-F = Ctrl-right-arrow.) ##### DO: Try some of the other cursor movement keys. Home takes you to the beginning (left) of the current line, while End moves the cursor to the end of the current line. Ctrl-Home moves the cursor to the top of the current screen, while Ctrl-End moves the cursor to the bottom of the current screen. Two other keys that are useful if your program is longer and will not all fit on one screen are the PgUp and PgDn keys. They move the cursor to the previous or next screen respectively. Also, Ctrl-PgUp moves to the very beginning of the file, while Ctrl-PgDn moves to the end of the file. (With only a few practice lines in your Work file, you may not see the benefit of these keys. Remember to try these combinations later when you are working with larger files.) 2. Inserting and Replacing Text There are two ways to type text when using an editor or word processor: 1. Insert new text while pushing existing text to the right to make room for the new text, and 2. Overwrite text by typing over the original text. (You may know this as the "Replace" mode or "Typeover" mode if you use other editors or word processors.) ##### DO Look at the top line of the screen while depressing the Ins key several times. The status line indicates whether "Insert" or î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 21 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 "Overwrite" mode is presently active. The Ins key is the way to switch between modes. ##### DO: Try using both modes on the text. Type this sentence: Today is a nice day. Change it to say it is a nice sunny day. The easiest way to do that (adding a new word) is to use insert mode. The text is inserted to the left of the cursor. Change sunny to rainy. The quickest way to do this is to use overwrite mode, since you want to replace one word with another. A very significant difference between Insert and Overwrite mode is the way the Enter key works in the two modes. With the editor in the insert mode, you can use the Enter key to open up new blank lines for inserting new lines of text or program. This doesn't work in the overwrite mode. ##### DO: Use the Ins key to put the editor in the Overwrite mode. Place the cursor at the beginning of one of your lines of text. Press the Enter key several times. What happens? ##### DO: Put the editor in the Insert mode. Press the Enter key several times. What results does this produce? REMEMBER THIS WHEN THE ENTER KEY DOESN'T SEEM TO WORK RIGHT! 3. Deleting Text There are several ways to delete text: 1. The Del key (or Ctrl-G) deletes the character at the cursor position and pulls the characters from the right. You might think of this as "eating" the characters to the right. 2. The backspace key (or Ctrl-H) deletes the character to the left of the cursor and pulls the characters from the right. This "eats" characters to the left. Note that this is not the same action as the left arrow key which moves the cursor left without deleting characters. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 22 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 3. Ctrl-Y deletes the entire line that the cursor is on. The previous two ways to delete just delete one character at a time while Ctrl-Y gives you a way to delete a whole line at a time. (Remember, the Enter key will open up a blank line when the editor is in the insert mode. Ctrl-Y doesn't leave a blank line where a line is deleted.) ##### DO: Try correcting the mistakes in your file by deleting mistakes and correcting them with either insert or overwrite. Type in more sentences with mistakes and try different ways to correct them to see for yourself how these different techniques work. Try deleting a whole line. You have tried the basics of entering and editing your program. Learning these now will save time and frustration later when you are working on programs! So if you are unsure how some of these work, go back and experiment with them until you are comfortable with the basic editing features. NOTE: THE REMAINDER OF LESSON 2 IS INTENDED TO HELP YOU GET "UP TO SPEED" USING THE TURBO PROGRAMMING ENVIRONMENT. THE EDITING AND FILE HANDLING SKILLS YOU DEVELOP NOW WILL SAVE TIME AND FRUSTRATION IN LATER LESSONS. 4. Experimenting On Your Own In the next lesson you will begin writing Pascal programs. How well you learn to program in Pascal will be determined by how well you teach yourself. Programming is learned best by programming, experimenting, trying things on your own. The ##### DO sections in these lessons are only intended to get you started. When you do the activities suggested, you will probably get ideas for other things to try. You should pursue your ideas--try to expand on the programs provided. The biggest obstacle to experimentation is the fear of "messing up" the program that is being built by the DO sections. The main purpose here is to provide enough practice SAVING and RETRIEVING a program so that you will have no fear of losing the "official" program while experimenting with programs of your own. 5. Saving and Retrieving Programs Because there is only one Editor Work file in the computer's memory at any one time, you need to be able to quickly save a file so you can experiment with a different one. When you are through experimenting, you can easily retrieve the program you were previously editing. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 23 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 Turbo makes it very easy to save your programs. Turbo will remind you to save your program if you are about to do something that would erase it. However, it is up to you to be sure your program is saved. To develop facility saving and retrieving files, you will edit and re-edit files named ONE, TWO, THREE, FOUR, and FIVE. You already have files named ONE and TWO. You will first add files THREE, FOUR, and FIVE with a short sentence in each. Then you will edit each file again to add your first name as the second line of each file. Finally, you will edit each file again, adding your last name. If you time yourself as you edit each of the five files the last time you may be surprised at how quickly you can carry out these essential file operations. ##### DO: Start a new file. ##### DO: Type: This is in file THREE. Save this file with the file name THREE. ##### DO: Create and save files FOUR and FIVE with the messages: This is in file FOUR and This is in file FIVE. If you have trouble with these steps, please refer back to lesson 1. 6. Re-Editing Each File At this point you will add a line with your first name to each file. Remember to use the Insert mode to enter the additional line. ##### DO: Load file ONE. Edit the file to add your first name as a second line of the file. To position the cursor at the beginning of a new line, first move it to the end of the existing line and press the enter key. (The editor must be in Insert mode). Save the file. ##### DO: Do the same Load, Edit, Save to add your first name to each of the other files. î TURBO-LESSONS - A Pascal Tutorial Version 5.0 Page 24 Copyright 1989 Lyle M. Faurot Lessons 1-16: $10.00 7. Getting Up to Speed As you edit the files one final time to add your last name, you might want to time yourself--you are getting pretty good at this by now! ##### DO: Add your last name following your first name in each of the files. That didn't take long, did it? REMEMBER: IN THE LESSONS THAT FOLLOW, IT'S QUITE EASY TO SAVE A PROGRAM, SO YOU CAN EXPERIMENT WITH YOUR OWN IDEAS.