[Kdar]

What are some differences between those languages?

Especially C vs. C++

and Perl vs. C/C++

The things that I can think of is that C and C++ are more platform-depended, C++ is more object oriented than C. C/C++ require compiler.
What else is there?

[CrazeD]

Typically C is more low-level, but most times you can do anything you need with C++.

Perl is a scripting language, and requires an interpreter. It can be used for web applications or light-weight system scripts.