how to use username instead of uid ?

[s4miii]

Hello, thank you for the great idea and the beautiful code you wrote. I wonder if there is a way we can switch to another user instead of root?I mean, is there any way to change this line setuid(0); to something like setuser(root); ? or better to ask, how to give the user's name instead of the user's uid?

I know my question may seem ridiculous, but I would be grateful if you could help me.

Thank you