-- Demonstrates declaring variables with ranges

-- Why: Better demonstrates programmer intent
-- Why: errors are caught as early as possible (on assignment, not later use)
-- Why: Allows program properties to be proved (discuss  later)

with ada.integer_text_io; use ada.integer_text_io; 
with ada.float_text_io; use ada.float_text_io; 
 
procedure ranges is 
    i : Integer range -50 .. 100;    -- Other values not allowed
    f : Float range 0.0 .. 100.0;

    n : Natural range 1 .. Natural'last - 1;
    p : Positive;

begin

    get(i);       -- Error if outside range -50 .. 100
    get(f);       -- Error if outside range

    put(i);       
    put(f);       

    i := -100;       -- Compiles but gives warning: constraint error at runtime

    get(n);          -- Runtime error possible?
    p := n + 1;      -- Runtime error possible?
end ranges;