// a very very inefficient method to calculate
// the number of days left in the current month
nDayLeftInMonth = 0
while MonthOf(Today() + nDayLeftInMonth) = MonthOf(Today())
sRESULT = 'Days left = ' + IntToStr(nDayLeftInMonth)
Some important points to note about these 2 operators. They do not return a value that is assigned to another variable; they operate directly on the variable.
inc(231) // incorrect !!!
inc(nDate + 12) // incorrect !!!
Because of this, you can only use these operators on integer variables, not on expressions as is the case with most other operators.