Question

Input: Month name (January / February / … / December)

Output: Season (Winter / Spring / Summer / Autumn)

Winter: Dec – Feb

Spring: Mar – May

Summer: Jun – Aug

Autumn: Sept – Nov

I have tried:

Program Months;

var
  Month:String;

begin
  writeln('Insert month name:');
  readln(Month);

  if Month = 'March' or Month = 'April' or Month = 'May' then

    begin
    writeln(Month,' is Spring month');
    end

    ...
    etc   
    ...

end.

But this program is not working.

Answer 1

Operator precedence – it’s important. You need to write:

if (Month = 'March') or (Month = 'April') or (Month = 'May') then

This is because in Pascal, or has a higher priority than = so what is actually being evaluated is:

if ((Month = ('March' or Month)) = ('April' or Month)) = 'May' then

Which is obviously meaningless and will not compile (I might’ve made a mistake on the line above but it’s the general idea). Please refer to this link to learn more about operator precedence in Pascal.