overload operator line 2 and 3, not compiling

Question

program PROG15 (input,output); var invalid_operator : boolean; operator : char; number1, number2, result : real;

procedure MULTIPLY;
begin
         result := number1 * number2
end;

procedure DIVIDE;
begin
         result := number1 / number2
end;

procedure ADD;
begin
         result := number1 + number2
end;

procedure SUBTRACT;
begin
         result := number1 - number2
end;

procedure GET_INPUT;
begin
         writeln('Enter two numbers and an operator in the format');
         writeln(' number1 operator number2');
         readln(number1); readln(operator); readln(number2)
end;

begin
         invalid_operator := FALSE;
         GET_INPUT;
         case operator of
             '*': MULTIPLY;
             '/': DIVIDE;
             '+': ADD;
             '-': SUBTRACT;
         otherwise invalid_operator := TRUE
         end;
         if invalid_operator then
            writeln('Invalid operator')
         else
            writeln(number1:4:2,' ', operator,' ', number2:4:2,' is '
                    ,result:5:2)
end.

{Special changes for Turbo are                           
         case operator of
             '*': result := MULTIPLY;
             '/': result := DIVIDE;
             '+': result := ADD;
             '-': result := SUBTRACT;
         else invalid_operator := TRUE
         end;         

Answer 1

Operator is probably reserved word due to operator overloading. Change its name.

Result is afaik not reserved (but a pseudo variable for the functions result in Delphi like modes), better give it a different name too.

You might also want to try enabling Turbo mode (-So)