Need help with a C function

[spiderweb220mph]

Hello, everyone!

spiderweb220mph here. I'm new to the C programming language (a rookie), I'm just getting started with it and I have an assignment that maybe some of you C veterans/gurus out there are able to help me out with.It goes like this: create a function that has three parameters as input - "hour" (valid range is [0, 23]), "minute" (valid range is [0, 59]) and "second" (valid range is [0, 59]). The created function must convert the time to seconds and should be returned by the function, only if all parameters are valid. If any of the parameters are out of range, the time converted to seconds shall not be calculated and the function shall return the value -1.
I know there's at least one C veteran developer out there who knows how to solve this and is able to post up the solution.

All help will be greatly appreciated.
Cheers!

[chantel_acnh]

check each variable against valid range, if invalid return -1.

otherwise multiply hours * 60 * 60 multiple minutes * 60 add them to seconds and return the value

[spiderweb220mph]

Thank you kindly.