> **1.** Section 15.1 listed several advantages of dividing a program into multiple source files.(a). Describe several other advantages > (b). Describe some disadvantages --- > **2.** Which of the following should *not* be put in a header file? Why not? b. Function definitions - Functions should only be defined once, and this allows multiple files to share the same function definition --- > **3.** We saw that writing `#include ` instead of `#include "file"` may not work if file is one that we've written. Would there be any problem with writing `$include "file"` instead of `#include ` if *file* is a system header? Yes, `""` is a path relative to the current file, whereas `<>` is a path to the system's standard library headers. --- > **4.** Assume that `debug.h` is a header file with the following contents... >(a). What is the output when the program is executed? ``` Output if DEBUG is defined: Value of i: 1 Value of j: 2 Value of i + j: 3 Value of 2 * i + j - k: 1 ``` > (b). What is the output if the `#define` directive is removed from `testdebug.c`? ``` Output if DEBUG is not defined: ``` > (c). Explain why the output is different in parts (a) and (b) When `DEBUG` is defined, any instances of the `PRINT_DEBUG` token are replaced with a `printf` call during compile time, but when it's not defined, they're replaced with nothing.