RosettaCodeData/Task/Odd-word-problem/Ada/odd-word-problem.ada

56 lines
1.2 KiB
Ada

with Ada.Text_IO;
procedure Odd_Word_Problem is
use Ada.Text_IO; -- Get, Put, and Look_Ahead
function Current return Character is
-- reads the current input character, without consuming it
End_Of_Line: Boolean;
C: Character;
begin
Look_Ahead(C, End_Of_Line);
if End_Of_Line then
raise Constraint_Error with "end of line before the terminating '.'";
end if;
return C;
end Current;
procedure Skip is
-- consumes the current input character
C: Character;
begin
Get(C);
end Skip;
function Is_Alpha(Ch: Character) return Boolean is
begin
return (Ch in 'a' .. 'z') or (Ch in 'A' .. 'Z');
end Is_Alpha;
procedure Odd_Word(C: Character) is
begin
if Is_Alpha(C) then
Skip;
Odd_Word(Current);
Put(C);
end if;
end Odd_Word;
begin -- Odd_Word_Problem
Put(Current);
while Is_Alpha(Current) loop -- read an even word
Skip;
Put(Current);
end loop;
if Current /= '.' then -- read an odd word
Skip;
Odd_Word(Current);
Put(Current);
if Current /= '.' then -- read the remaining words
Skip;
Odd_Word_Problem;
end if;
end if;
end Odd_Word_Problem;