case operation of '+': result := num1 + num2; '-': result := num1 - num2; '': result := num1 num2; '/': begin if num2 <> 0 then result := num1 / num2 else begin writeln('Error: division by zero'); exit; end; end; else begin writeln('Error: invalid operation'); exit; end; end;
program Calculator;
var
num1, num2, result: real;
operation: char;
begin
write('Enter first number: ');
readln(num1);
write('Enter second number: ');
readln(num2);
write('Enter operation (+ - * /): ');
readln(operation);
case operation of
'+': result := num1 + num2;
'-': result := num1 - num2;
'': result := num1 num2;
'/': begin
if num2 <> 0 then
result := num1 / num2
else
begin
writeln('Error: division by zero');
exit;
end;
end;
else
begin
writeln('Error: invalid operation');
exit;
end;
end;
writeln('Result: ', result:0:2);
end.