### Changing an ITimeStamp Object

You can add seconds to, or subtract seconds from, an ITimeStamp object. You can also subtract one ITimeStamp object from another, in which case the result is the number of seconds between the two timestamps. For example:

    ITimeStamp TmStamp1, TmStamp2;
    double diff;
    TmStamp1 = ITimeStamp::currentTimeStamp();
    TmStamp2 = TmStamp1 + 4000.0;              // 4000.0 seconds after TmStamp1
    TmStamp2 -= 1000.0;                        // go back 1000.0 seconds
    diff = TmStamp2 - TmStamp1;                // should be 3000.0 seconds different
                                               //    (if there is no rounding error)

Note: You cannot add two ITimeStamp objects together, as such an addition does not make sense. Also, all the operations are done using floating point arithmetic. As a result, some error due to rounding may occur.