Perform Roman numeral arithmetic.
#!/usr/local/bin/bush
procedure roman_numerals is
pragma annotate( "Roman Numerals" );
pragma annotate( "" );
pragma annotate( "Roman numeral arithmetic adapted from an Ada to BUSH" );
pragma annotate( "adapted by Ken O. Burtch" );
pragma ada_95;
pragma restriction( no_external_commands );
-- Declare variables which will be used in main program out here
MaxRomanLength : constant positive := 20;
subtype RomanNumeralType is string;
--------------------------------------------------------------------------------
-- Function for checking Valid Input from the user
-- This function returns a boolean value
function ValidRomanNumeral (PossibleNumeral : RomanNumeralType) return
boolean is
Position : positive := 1; -- position we are checking in the input
begin -- ValidRomanNumeral
if strings.length( PossibleNumeral ) > natural( MaxRomanLength ) then
return false;
end if;
if strings.length( PossibleNumeral ) = 0 then
return false;
end if;
loop
if Position = MaxRomanLength then
return true; -- we have reached the maximum length without problems
elsif Position > positive( strings.length( PossibleNumeral ) ) then
return true; -- we have reached the actual end without problems
elsif strings.element( PossibleNumeral, Position) = 'I'
or strings.element( PossibleNumeral, Position) = 'V'
or strings.element( PossibleNumeral, Position) = 'X'
or strings.element( PossibleNumeral, Position) = 'L'
or strings.element( PossibleNumeral, Position) = 'C'
or strings.element( PossibleNumeral, Position) = 'D'
or strings.element( PossibleNumeral, Position) = 'M' then
Position := Position + 1;
else
return false; -- we have a problem, so return false
end if;
end loop;
-- This will never happen.
return false;
end ValidRomanNumeral;
--------------------------------------------------------------------------------
function RomanToNatural (RomanNumeral : RomanNumeralType) return natural is
Result : natural := 0; -- result variable
CurrentPosition : positive := 1; -- the current position in RomanNumeral being examined.
Value : integer:=0; -- Value of the corresponding roman numeral
First : integer:=0;
Next : integer:=0;
begin --RomanToNatural
-- Loop to process the appropriate value from the user
loop
if CurrentPosition > positive( strings.length( RomanNumeral ) ) then
exit;
elsif strings.element( RomanNumeral, CurrentPosition) = 'M' then
Value := 1000;
elsif strings.element( RomanNumeral, CurrentPosition) = 'D' then
Value := 500;
elsif strings.element( RomanNumeral, CurrentPosition) = 'C' then
Value := 100;
elsif strings.element( RomanNumeral, CurrentPosition) = 'L' then
Value := 50;
elsif strings.element( RomanNumeral, CurrentPosition) = 'X' then
Value := 10;
elsif strings.element( RomanNumeral, CurrentPosition) = 'V' then
Value := 5;
elsif strings.element( RomanNumeral, CurrentPosition) = 'I' then
Value := 1;
end if;
-- If this is the first character then store the value
-- of it in the variable 'First'
if CurrentPosition = 1 then
First := Value;
end if;
Next := Value; -- Store the second value in this variable(2nd iteration)
-- This is for the second Iteration. Check if the second value
-- is greater than the first value and perform the nescassary
-- steps.
if First < Next then
Result := natural(Next - First) +Result - natural(First);
else
Result := Result + natural(Next);
end if;
-- Assign the value of first to next
-- for comparison in later cases
First := Next;
CurrentPosition := CurrentPosition + 1; -- Increment the counter Variable
end loop; -- End the loop here
return Result; -- Return the final result to where function is being called
end RomanToNatural; -- End the function
--------------------------------------------------------------------------------
-- This Function Gets a valid choice from the user
-- The user can chooose to perform arithmetic operations on the
-- Roman numerals. The choices are 1 through 4.
-- Will keep looping till the user gives correct Choice
function GetValidChoice return integer is
ValidChoice : integer;
Choice : integer:=1;
begin
loop
new_line;
put("Please choose one of the following operations to be performed:");
new_line;
put("1) Add the two Roman Numerals.");
new_line;
put("2) Subtract the two Roman Numerals.");
new_line;
put("3) Multiply the two Roman Numerals.");
new_line;
put("4) Divide the two Roman Numerals.");
new_line;
put("----------------------------------------------------");
new_line;
put("Please enter choice: ");
Choice := numerics.value( get_line );
if (Choice>0) or (Choice<=4) then
exit;
else
new_line;
put("Please enter Valid Choice.");
new_line;
end if;
end loop;
ValidChoice := Choice;
return ValidChoice;
end GetValidChoice;
--------------------------------------------------------------------------------
-- This procedure process the valid choice and performs the
-- nescassary calculations on the Two user inputs
function ProcessChoice(UserInput1 : natural;
UserInput2 : natural;
Choice : integer ) return natural is
Output : natural;
-- Write this procedure in the morning
-- what this essentially does is
-- it takes in userinput1 and userinput2 and Choice as IN Variables
-- According to the user's specified choice we can then compute the possible
-- values and return Output
-- This value of output will the in turn be stored in a variable called
-- FinalInteger
-- declare variables here
Plus : natural:=0;
Minus : natural:=0;
Multiply : natural:=0;
Divide : natural:=0;
begin -- ProcessChoice
-- Start checking for user choice and perform nescassary action
if (Choice = 1) then
Plus := UserInput1 + UserInput2;
Output := Plus;
elsif (Choice = 2) then
Minus := UserInput1 - UserInput2;
Output := Minus;
elsif (Choice = 3) then
Multiply := UserInput1 * UserInput2;
Output := Multiply;
elsif (Choice = 4) then
Divide := UserInput1 / UserInput2;
Output := Divide;
else
put("SOMETHING HAS GONE WRONG");
end if;
return Output;
end ProcessChoice;
-------------------------------------------------------------------------
procedure ConvertBack(ConvertWhat : natural) is
Value : natural;
begin
Value := ConvertWhat;
for I in 1..20 loop
if Value<=4000 and Value>=1 then
while Value>=1000 loop
put( "M" );
Value:=Value - 1000;
end loop;
while Value>=500 loop
put( "D" );
Value:=Value - 500;
end loop;
while Value>=100 loop
put( "C" );
Value:=Value - 100;
end loop;
while Value>=50 loop
put( "L" );
Value:=Value - 50;
end loop;
while Value>=10 loop
put( "X" );
Value:=Value - 10;
end loop;
while Value>=5 loop
put( "V" );
Value:=Value - 5;
end loop;
while Value>=1 loop
put( "I" );
Value:=Value - 1;
end loop;
end if;
end loop;
new_line;
end ConvertBack;
--------------------------------------------------------------------------------
RomanNumeral1 : RomanNumeralType;
RomanNumeral2 : RomanNumeralType;
FinalInteger : natural:=0;
Input1 : natural:=0;
Input2 : natural:=0;
UserChoice : integer:=0;
begin -- Procedure Roman
put("Welcome to the Roman Numeral Calculator program:");
new_line;
new_line;
-- Get the valid roman numeral from the user
-- This function returns two integer values in RomanInteger1 and RomanInteger2
-- These values are the corresponding integer values of the entered roman numerals
loop
put( "Please enter the FIRST Roman numeral: ");
RomanNumeral1 := get_line;
put( "Please enter the SECOND Roman numeral: ");
RomanNumeral2 := get_line;
if ValidRomanNumeral(RomanNumeral1) then
if ValidRomanNumeral(RomanNumeral2) then
exit;
end if;
end if;
put( "Please make sure BOTH the Roman Numerals are valid and try again");
new_line;
end loop;
Input1 := RomanToNatural( RomanNumeral1 );
Input2 := RomanToNatural( RomanNumeral2 );
UserChoice := GetValidChoice;
FinalInteger := ProcessChoice(Input1,Input2,UserChoice);
put( "Final Result is: " );
ConvertBack(FinalInteger);
end roman_numerals;
-- VIM editor formatting instructions -- vim: ft=bush