Week 5: Preprocessor

Question 1

What does the preprocesser make up one half of?

Answer 1

The compiler directive, the other half being the compiler.

Question 2

In a nutshell, what does the preprocessor do?

Answer 2

Finds #include file and #define macros.
Include files are programatically placed where the #include tags are.
Defined macros are replaced throughout the program.

Question 3

What are the 2 main benefits of macro pre-processing?

Answer 3

• Reduces overhead on the call stack, thus improves efficiency.
• Enables elimination of global variables.

Question 4

What does the command line argument ggc -I do?

Answer 4

Specifies a search path for the compiler.

Question 5

Define the difference between #include < > and #include “ “

Answer 5

< > makes the compiler search the standard path.
“ “ makes the compiler search the immediate directory of the program.

Question 6

What is selective compilation?

Answer 6

Enables conditional statements to be executed in the context of pre-processing.

Question 7

What are the 6 main selective compilation tags?

Answer 7

ifdef
ifndef,
else
elif
endif
undef -> Undefines a macro or symbol.

Question 8

What are the 5 most useful predefined macros?

Answer 8

__FILE__
__LINE__
__DATE__
__STDC__
__TIME__