notes/education/software development/ECE1400/Chapter 15 Exercises.md

1. Section 15.1 listed several advantages of dividing a program into multiple source files.(a). Describe several other advantages

(b). Describe some disadvantages

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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

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3. We saw that writing #include <file> 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 <file> 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.

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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.

(d). Is it necessary for the DEBUG macro to be defined before debug.h is included in order for PRINT_DEBUG to have the desired effect? Justify your answer.

Macro invocations are evaluated sequentially, and so if DEBUG was defined after PRINT_DEBUG, then any usages of PRINT_EVALUATION would be have like DEBUG was not defined.