16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] to Computers & ProgrammingAdaProf. I. Kristina LundqvistDept. of Aero/Astro, MIT16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] program§ Display a message: “Hello there. We hope you enjoy studying Ada!”§ Pseudo code: put (Hello there. We hope you enjoy studying Ada!)WITH Ada.Text_IO; -- declare the packagePROCEDURE Hello IS--------------------------------------------------------------| A very simple program; it just displays a greeting.--| Author: Michael Feldman, The George Washington University--| Last Modified: June 1998------------------------------------------------------------BEGIN -- HelloAda.Text_IO.Put(Item => "Hello there. ");Ada.Text_IO.Put(Item => "We hope you enjoy studying Ada!");Ada.Text_IO.New_Line;END Hello;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] — February 10/2003 — Prof. I. K. Lundqvist — [email protected] Spider;PROCEDURE Walk_Line IS---------------------------------------------------------------| Walk line with spider--| Author: M. B. Feldman, The George Washington University --| Last Modified: July 1998-------------------------------------------------------------BEGIN -- Walk_LineSpider.Start;Spider.Step;Spider.Step;Spider.Step;Spider.Step;Spider.Step;Spider.Quit;END Walk_Line;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] Spider Package (spider.ads)§ A package is a way to encapsulate, or group, a set of related operations.§ Divided into 2 parts§ Specification .ads“table of contents”§ Body .adbactual program segments§ Standard Ada packages are “built in”, i.e., provided by the compiler§ Standard (+, -, …, characters)§ Character (Is_upper, To_Lower,…)§ Numerics (Sqrt, Log, …)§ Text_IO (get, put, open, …)§ …16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] Spider Package (spider.adb)PROCEDURE Start ISBEGINDrawRoom;CurrentColumn := 10; -- these are in the spider's viewCurrentRow := 11;Heading := North;ChangeColor(NewColor => Green);ShowSpider;ShowDirection;RandomSteps.Reset(Gen => GSteps);RandomColors.Reset(Gen => GColors);RandomDirections.Reset(Gen => GDirections);END Start;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] walk_boxWITH Spider;PROCEDURE Walk_Box IS-----------------------------------------| Walk 4 x 4 box with spider--| Author: M. B. Feldman, The GWU --| Last Modified: July 1998---------------------------------------BEGIN -- Walk_BoxSpider.Start;Spider.Step;Spider.Step;Spider.Step;Spider.TurnRight;Spider.Step;Spider.Step;Spider.Step;Spider.TurnRight;Spider.Step;Spider.Step;Spider.Step;Spider.TurnRight;Spider.Step;Spider.Step;Spider.Step;Spider.TurnRight;Spider.Quit;END Walk_Box;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] — February 10/2003 — Prof. I. K. Lundqvist — [email protected] with Single Loop§ Algorithm for drawing box1. Repeat steps a and b 4 timesa. Take 3 steps forwardb. Turn right§ A repetition is usually called a loop§ Use an Ada control structure called the FORconstruct:FOR Side IN 1..4 LOOPandEND LOOP;WITH Spider;PROCEDURE Draw_Box_with_1_Loop IS-----------------------------------------| Draw 4 x 4 box with spider - use loop--| Author: M. B. Feldman, The GWU--| Last Modified: July 1998---------------------------------------BEGIN -- Draw_Box_with_1_LoopSpider.Start;Spider.ChangeColor(NewColor => Spider.Red);FOR Side IN 1..4 LOOPSpider.Step;Spider.Step;Spider.Step;Spider.TurnRight;END LOOP;Spider.Quit;END Draw_Box_with_1_Loop;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] and Writing Numbers§ Calculate the sum and product of two numbers§ Algorithm:§ Get the 2 numbers§ Ask for the 2 numbers§ Get number1§ Get number2§ Calculate and print the sum§ Print “The sum is “§ Print (number1 + number2)§ Calculate and print the product§ Print “The product is “§ Print (number1 * number2)§ Pseudo codeNumber1: numberNumber2: numberPut (give me two whole numbers)Get (number1)Get (number2)Put (the sum of the numbers is )Put (number1 + number2)Put (the product of the numbers is )Put (number1 * number2)16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected]_prod§ --------------------------------------------------------- sum_prod - sum and product, Skansholm #2.4.2 -------------------------------------------------------with Text_Io; -- specify packages we depend on use Text_Io;procedure Sum_Prod is -- declare integer I/O packagepackage Int_Io is new Text_Io.Integer_Io(Integer);use Int_Io;-- declare any constants and variables requiredNumber1, Number2 : Integer; -- numbers used begin -- sum_prod -- ask user for numbers and read them Put_Line("Give me two whole numbers!");Get(Number1);Get(Number2); -- display sum and product of numbers Put("The sum of the numbers is:");Put(Number1+Number2);New_Line;Put("The product of the numbers is:");Put(Number1*Number2);New_Line;end Sum_Prod;16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected] — February 10/2003 — Prof. I. K. Lundqvist — [email protected] solutionwith Text_Io; use Text_Io;procedure Sum_Prod is -- declare integer I/O package package Int_Io is new Text_Io.Integer_Io( Integer );use Int_Io;-- declare any constants and variables required Number1, Number2, Total, Product : Integer; begin -- sum_prod -- ask user for numbers and read them Put ( "Please enter the first number ");Get ( Number1 ); Skip_Line;Put ( "Please enter the second number ");Get ( Number2 ); Skip_Line;-- display sum and product of numbers Total := Number1 + Number2;Product := Number1 * Number2;Put("The sum of the numbers is:");Put(Total, Width=>7); New_Line;Put("The product of the numbers is:");Put(Product, Width=>3); New_Line;end Sum_Prod;Layout conventionsone statement (thought) per linebreak long lines into readable segmentsindent lines to show different parts of the programblank lines separate parts of the programcomments/header to help readers understand the program16.070 — February 10/2003 — Prof. I. K. Lundqvist — [email protected]§ Lines starting with -- are ignored by the compiler. Only there to help someone reading the program § Good comments: § are always correct and up to date § conform to usual conventions of prose §
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