program CheckDigits;
var
number, digit1, digit2, digit3: Integer;
begin
write('Enter a 3-digit number: ');
readln(number);
digit1 := number div 100;
digit2 := number div 10 mod 10;
digit3 := number mod 10;
if (digit1 = digit2) and (digit2 = digit3) then
writeln('Digits are equal')
else
writeln('Digits are not equal');
end.

Пример работы программы:

Enter a 3-digit number: 111
Digits are equal
Enter a 3-digit number: 123
Digits are not equal