Chapter 6 - Functions

Question 1

Define: Code reuse

Answer 1

Write the code to perform a task ONCE, then reuse it each time you need to perform the task.

Question 2

Define: Function call

Answer 2

A statement that causes a function to execute.

Question 3

Define: Function Definition

Answer 3

Contains the statements that make up the function.

Question 4

All function definitions have what 4 parts?

Answer 4

1) Return Type
2) Name
3) Parameter list
4) Body

Question 5

Define: Return type (of a function)

Answer 5

#1
data type of the value that is sent FROM the function 
listed first 
int main() --> int is the RETURN TYPE

Question 6

Define: Name (of a function)

Answer 6

#2
Should give each function a descriptive name - in general, same rules apply as to variables for naming
int main() --> main is the NAME

Question 7

Define: Parameter List (of a function)

Answer 7

#3
List of variables that hold the values being passed TO the function
int main() --> () is the parameter list (it's empty!)

Question 8

Define: Body (of a function)

Answer 8

The set of statements that perform the function's operation. 
enclosed in a set of braces
int main() 
{
BODY HERE
}

Question 9

Define: Function Header

Answer 9

The line in the definition that reads int main() (the first line)

Question 10

Define: Void functions (they return….)

Answer 10

Some function simply perform one or more statements and then terminate, without returning a value. these are VOID functions. 
Example:
void displayMessage()
{
     cout << "hello from the function displayMessage. \n";
}

Notice: not return statement

Question 11

void displayMessage()
{
     cout << "hello from the function displayMessage. \n";
}
What part is the function header? 
How would you "call" this function?

Answer 11

Function Header: void displayMessage()

Call: displayMessage();

Question 12

Fuction prototypes are also known as …

Answer 12

Function declarations

Question 13

You must place either the function definition or the function prototype _______ all calls to the functions.
What happens if you don’t?

Answer 13

BEFORE

Or else the program will not compile

Question 14

What would a “function prototype” for the following function definition be? What’s different about it?

void displayMessage()
{
     cout << "hello from the function displayMessage. \n";
}

Answer 14

void displayMessage();
- semicolon at the end

Tells compiler the function displayMessage has a void return type (doesn’t return a value) and uses no parameters.

Question 15

When a function is called, the program may send _____ into the function.

Answer 15

VALUES

Question 16

Values sent into a function are called ___________.

Answer 16

arguments

Question 17

Define: Parameter

Answer 17

a special variable that holds a value being passed into a function.
For example:
void displayValue(int num)
{
court &laquo_space;“The value is “ &laquo_space;num &laquo_space;endl;
}
The variable num is the parameter.

Question 18

For this function definition, what would the prototype be that you could use at the top?
void displayValue(int num)
{
     court << "The value is " << num << endl;
}

Answer 18

void displayValue(int);

Question 19

How would you call the function of this prototype:
void displayValue(int);

Answer 19

displayValue(5); (this could be any integer where the argument 5 is)

Question 20

What could the function body be for the following function:

void displayValue(int);

Answer 20

void displayValue(int num)
{
     cout << "The value is " << num << endl;
}

Question 21

WARNING!
When passing a variable as an argument, simply write the variable name inside the parenthese of the function call. Do not write the _____ _____ of the argument.

Answer 21

Data Type.
displayValue(int x); // Error!

Call should appear as:
displayValue(x); // Correct

Question 22

If you pass an argument whose TYPE is not the same as the parameter’s type, the argument will be ________ or _________ automatically.

Answer 22

promoted or demoted
Ex: the following function call would be truncated (because the parameter is an integer not double):
displayValue(4.7);

Question 23

WARNING!
Each parameter variable in a parameter list must have a _____ _____ listed before its name.
Provide an example.

Answer 23

Data Type:
void showSum (int num1, num2,  num3) // ERROR!

void showSum (int num1, int num2, int num3) // Correct

Question 24

When a function with multiple parameters is called, the arguments are passed to the parameter in ______.

Answer 24

order.

example: showSum(5, 10, 15); passes 5, 10, 15 in that order ….

Question 25

When an argument is passed into a parameter, only a _____ of the argument’s value is passed.

Changes to the parameter do not affect the ______ argument.

Answer 25

When an argument is passed into a parameter, only a copy of the argument’s value is passed.

Changes to the parameter do not affect the original argument.

Question 26

The return Statement causes a function to …

Answer 26

end immediately

Question 27

Functions that return a value are known as….

Answer 27

value-returning functions

Question 28

The power function is an example of a ______-_____ function.
double x;
x = pow(4.0, 2.0);

Answer 28

value-returning function
double x;
x = pow(4.0, 2.0);

The 2nd line calls the pow function, passing 4.0 and 2.0 as arguments.
the function calculates the value of 4.0 raised to the power of 2.0 and returns the value, which is 16.0 and is assigned to the x variable by the = operator.

Question 29

Although several arguments may be passed into a function, only one ______ may be returned from it.

Answer 29

value

Question 30

int sum(int num1, int num2)
What is the Return Type?

Answer 30

int

Question 31

What is the general format of a return statement?

Answer 31

return expression;

Question 32

The return expression can be any expression that has a _______, such as…..

Answer 32

The return expression can be any expression that has a value, such as a variable, literal, or mathematical expression.

Question 33

A local variable is defined ______ a function and not accessible ______ the function.

Answer 33

A local variable is defined inside a function and not accessible outside the function.