How to link g++ itself to my project?

so to make things clear, my goal is to write a code which can save crucial parts of its own code (like the main func or other classes or stuff like that) which i will be just copying them inside a class, then i want my program to add/remove some codes (func, obj, class, ...) using user input and after all of that i want it to regenerate that code again and create the class that holds the crucial parts of the code automatically and i want it to compile that and delete itself.

So i have all of the above planned and figured out except the part which i want it to compile that code, is there anyway to link g++ to my code? but i know that g++ has a main func, wouldnt that create problems with my main func? + i cant use the compiler on the existing system and i cant have the compiler as a separate executable...