title: Turbo Pascal: check if string contains numbers
body: <p>As it's said in the title Im having trouble finding a solution on how to check if a string <code>PW</code> contains a number or not. How can i check in TP if the string <code>PW</code> contains a digit?   </p>
  
  <pre><code>repeat
          writeln;
          writeln('Ok, please enter your future password.');
          writeln('Attention: The Text can only be decoded with the same PW');
          readln(PW);
          pwLength:= Length(PW);
          error:=0;
            for i:= 1 to Length(PW) do begin
              if Input[i] in ['0'..'9'] then begin
              error:=1;
              end;
            end;
  
             if Length(PW)=0 then
             begin
             error:=1;
             end;
  
              if Length(PW)&gt;25 then
              begin
              error:=1;
              end;
  
          if error=1 then
          begin
          writeln('ERROR: Your PW has to contain at least 1character, no numbers and has to be under 25characters long.');
          readln;
          clrscr;
          end;
  
        until error=0;
  </code></pre>