compilers

how do compilers work ?
i mean when you have say c or c++ code or lisp program, how does it turn it into machine code ?
isnt it too complicated and take a lot of machine code ?
or like scheme tail loop, how is it done . its hard to convert just one loop
or like c++ classes theres no clases in machine assmebly
i dont understand

thanks

Compilers work because everything the source language can do is possible in the machine language, it just has to be expressed differently and in gruesome detail.  C is not overly hard to write a compiler for as it's pretty damn low level as it is.  Many concepts in C map almost directly to assembler.