03 - Functions

Question 1

Functions in C are most like what in Java?

• Static methods
• Public methods
• Private methods

Answer 1

Static methods

Question 2

How many options can an ‘‘if’ statement choose between?

Answer 2

2
More conditions can be used by breaking them down into two compound conditions.

e.g. if ((x || y) && z){}

Question 3

What will be the final value of ‘x’ after the following code?

int x = -1;
if(x){
    x = 1
} else {
    x = 2
}

Answer 3

x = 1

An if statement will count any non-zero value as true

Question 4

What is a function prototype?

Answer 4

A function prototype is a way of declaring a function without its body. It simply lets the program know that the function exists, allowing the compiler to check its use, without knowing what it actually calculates/outputs

Question 5

Is this a valid function prototype?

int add(int, int);

Answer 5

Yes

It’s not necessary to give names to the arguments - just their types.

Question 6

Which of these are you not likely to find in a header file?

• Function prototypes
• Macro definitions
• Function definitions
• Constant variable declarations

Answer 6

Function definitions

These cannot be included in a header file that is intended to be used in more than one C file, as a function can only be defined once in the entire program

Question 7

What happens if you use a function without declaring it first?

Answer 7

C will guess a prototype, based on how it has been called.

It will assume the function returns an integer, and will guess the argument types based on what you have provided