1976:

        IDAY = IDAY + 1
        IDOLLAR = IDOLLAR + 1

1978:

100 D = D + 1
110 M = M + 1

1979:

        INC DAY
        INC DOLLAR

1984:

day := day + 1
dollar := dollar + 1

1986:

day++, dollar++;

1988:

day.another(); dollar.another();

1999:

public interface WorkForALiving {
  void another_day();
  void another_dollar();
}

2003:

day += 1; dollar += 1