A very simple Ada Calculator - My version of a Hello World

calculator.adb

-- Written by Eliot Brown on 26th September 2012

--A basic calculator that can calculate * + - /
--of two real numbers

with TEXT_IO; use TEXT_IO;
procedure CALCULATOR is
	type REAL is digits 20; --20 digit numbers
	package IO_REAL is new FLOAT_IO(REAL); use IO_REAL;
	A, B, C: Real --Declare A, B, C are real. Note, C is the result
	OPERAND: CHARACTER; --Declare the operand as a character. + - * / acceptable
begin
	while not END_OF_FILE(STANDARD_INPUT) loop
		GET(A); GET(OPERAND); GET(B); --read the input
		case OPERAND is
			when '+' => C := A+B;
			when '-' => C := A-B;
			when '*' => C := A*B;
			when '/' => C := A/B;
			when others => PUT("Error, bad operator");
				exit; --Exit only on bad input
		end case;
	PUT(RESULT);NEW_LINE;
	end loop;
end CALCULATOR;