1.       Use the Time class to provide an overloaded ‘−’. Here the time query is also to be recorded in a fi le. Use C text fi le to store the query. If a calling function provides expression Time1 − Time2, then operator –() function should throw an exception if Time2 is a later time than Time1. Before throwing the exception, though, the operator ‘−’ function should close the fi le.

2.       Using Time class, throw an exception when invalid time is input. Write set_terminate() to provide your own terminate function, which takes care of this problem.