Useful Ada Information

Help for programming assignment

Clarifications

• You must read and write the moves directly – you may NOT convert them to strings for printing.

• You should print out the number of ties as well as the number of computer wins and user wins

• You need to handle the situation where the user types in rack or scisssors or piper (for example)

• If an exception occurs, you need to handle it and continue until either the user or the computer has won 3 games.

• Don’t use use clauses

Declaring a user-defined type(enumeration type)

• type typename is ( elementList );

• elementList → element

• elementList → element , {elementList}

• element can not be numeric

• element can not contain a reserved word

• element can not have spaces in it

Examples

• type car is (ford, chevy, lincoln, bmw);

• type city is (rome, naples, bologna);

• type die is (1,2,3,4,5,6);

• type die is (one, two, three, four, five,six);

• type city is (new york, paris);

• type city is (old town, paris);

Instantiating an enumeration type

• package name_io is new ada.text_io.enumeration_io (enum => type);

• instantiation allows reading and writing of enumerated type variables

• enum is the formal parameter name• => is called arrow• this example uses named parameter passing• formal parameter name is NOT required

Here’s the Ada specification for the procedure to print an integer

Procedure put (item : in Num;

width : in Field := Default_Width;

base : in Number_Base := Default_base;

• The default_base is 10• The default_width is num’width

• Given an integer variable named number• The following are equivalent calls to this procedure

Ada.integer_text_io.put (number);

Ada.integer_text_io.put (item => number);

Procedure put (continued)

• Given an integer variable named number, suppose you want the column width of your output to be 10 and you want to use the default base

• The following statements produce the same results• Ada.integer_text_io.put (number, 10);• Ada.integer_text_io.put (item => number, width => 10);• Ada.integer_text_io.put (width => 10, item => number);• Ada.integer_text_io.put (item => number, width => 10,

base => 10;• Ada.integer_text_io.put (number, 10, 10);• Ada.integer_text_io.put (base =>10, item => number,

width => 10);

Examples

• type car is (ford, chevy, lincoln, bmw);

• package car_io is new ada.text_io.enumeration_io (enum => car);

• type city is (rome, naples, bologna);

• package city_io is new ada.text_io.enumeration_io (city);

Examples

• type car is (ford, chevy, lincoln, bmw);

• package car_io is new ada.text_io.enumeration_io (enum => car);

• myCar : car;

• car_io.get( myCar);

• car_io.put (myCar);

Enumeration types have attributes

• typename’pos

• typename’val

• typename’first

• typename’last

• The enumeration type’s element list is ordered

• The first element is in position 0

Ada Random Number Generator

• The information on random number generation can be found in the Language Reference Manual at

• http://www.adahome.com/rm95/rm9x-A-05-02.html• Here is an example of code from the above site using Ada’s random number generator

• with Ada.Numerics.Discrete_Random; • procedure Dice_Game is • subtype Die is Integer range 1 .. 6; • subtype Dice is Integer range 2*Die'First .. 2*Die'Last; • package Random_Die is new Ada.Numerics.Discrete_Random (Die); • use Random_Die; • G : Generator; • D : Dice; • begin • Reset (G); -- Start the generator in a unique state in each run • loop -- Roll a pair of dice; sum and process the results • D := Random(G) + Random(G); ... • end loop; • end Dice_Game;

Ada subprograms

• can be separately compiled• can be separately executed

– execution only shows if there is output

• ada subprogram specifications – have extension .ads– header ends in a semicolon

• Ada subprogram bodies – have extension .adb– header ends in reserved word is

Ada functions

• Function body (i.e. Dot_Product.adb) below comes from the language reference manual

http://www.adahome.com/rm95/rm9x-06-03.html

function Dot_Product(Left, Right : Vector) return Real isSum : Real := 0.0; begin Check(Left'First = Right'First and Left'Last = Right'Last); for J in Left'Range loop Sum := Sum + Left(J)*Right(J); end loop; return Sum; end Dot_Product;

Ada procedures• subprogram_body ::= subprogram_specification is declarative_part

begin handled_sequence_of_statements end [designator];

procedure Push(E : in Element_Type; S : in out Stack) is begin if S.Index = S.Size then

raise Stack_Overflow; else S.Index := S.Index + 1; S.Space(S.Index) := E; end if; end Push;

above Procedure example can be found at http://www.adahome.com/rm95/rm9x-06-03.html