P&A - Functions in C

Question 1

Functional decomposition

Answer 1

Functions break a larger program into smaller parts

Question 2

How would you define a function?

Answer 2

return type function_name(parameter declarations)
{
variable declarations
Statements
}

Question 3

Entry point

Answer 3

Where the program starts running

In C, it’s the main() function

Question 4

Function parameters

Answer 4

Allow us to pass a value from one function to another

e.g. numSwap(int num1, int num2)

Function parameters are automatic variables and are initialised with a copy of the value passed (pass by value)

Question 5

Pass by value

Answer 5

Function parameters are automatic variables and are initialised with a copy of the value passed (pass by value)

Question 6

What is the lifetime and scope of a function’s variables?

Answer 6

As the variables in a function are automatic, the scope is local to the function, and have a lifetime of only when the function is running

Question 7

How many values can a function return at once?

Answer 7

One (single value)

Question 8

void keyword

Answer 8

Used to declare that there is no return value, or can also use to declare no parameters

Question 9

printf() function library?

Question 10

what are the conversion characters to print the following:

strings
unsigned decimal
float
double
int

Answer 10

string - %s
unsigned decimal - %u
float - %f
double - %lf 
int - %d

Question 11

escape characters

Answer 11

\n - new line
\t - tab 
\b - backspace 
\" - double quote
\\ - backslash