C Programming 03

Question 1

What does the ? operator provide?

Answer 1

Can be used for a shorthand for if-else in an expression.
e.g
condition ? expression if true : expression if false;
or
max = (a > b) ? a : b;

Question 2

How is a string represented in C?

Answer 2

An array of chars terminated by the NULL character ‘\0’

Compiler adds 0 at end of array so make length of array big enough

Question 3

What is #ifdef?

Answer 3

A preprocessor directive which include some code only if a symbol is defined
e.g
#ifdef X
..
#else
..
#endif

Question 4

Why use macro functions?

Answer 4

• Don’t need to worry about types

* Useful for things which aren’t valid code

Question 5

What is a header guard?

Answer 5

#ifndef POINT_H_
#define POINT_H_
typedef struct { int x, y } point;
#endif