I am new to the programming field. I have been looking for examples of, or resources to the adding or subtracting of time variables in C/C++.

For example: given the time 20:30 Monday night and 04:30 Tuesday morning what is the difference?
Also adding 14:30 + 30:00 = 44:30.

I'm just looking for a starting place. All the time functions I've come across only have to do with obtaining the current date and time from the operating system. I'm looking to build a program that can manipulate given times somewhat like what an employer would need for managing a timeclock (I'm not an employer).

Thanx,

JCCC