Procedure alphanum

Procedure alphanum (Var t:tab;Var ch:String);
Var
  x,j: Integer;
  L,i: Char;
Begin
  For i:='A' To 'Z' Do
    t[i] := 0;
  x := Length (ch);
  For j:=1 To Length(ch) Do
    Begin
      L := ch[j];
      If L In ['A'..'Z'] Then t[ L ] := t[ L ] +1;
    End;
End;