Answer from cs61c-eo (James McBryan 16730959) for Question 1
The purpose of the C preprocessor is to replace code in a program to make it more less error prone.  Its input is C language.. thus the "C" in its name.  Its output is also C code that varies from spaces in strings to predefined variable names.  The C preprocessor would take place right before the compiler into another "assembler" area.  It is like taking pseduo-code in C and making it more C.