Objective C is a programming language based on the classic “C” language, with object oriented capabilities added to it. It is not the next version of C. C++ is another language based on C that many people consider as “the next version of C”. But that is debatable. Objective C came out much later than C++.
Objective C was originally created for the NeXT Step PC, which is the computer system touted by Steve Jobs after he was fired from Apple Computer.
Today, Objective C is primarily used for writing software for the Macintosh and the iPhone.
The language is designed to provide Smalltalk like messaging to a C like language. It is an object oriented language, but it is noticeably different from C++.