Chapter 6 - Functions Flashcards
(33 cards)
Define: Code reuse
Write the code to perform a task ONCE, then reuse it each time you need to perform the task.
Define: Function call
A statement that causes a function to execute.
Define: Function Definition
Contains the statements that make up the function.
All function definitions have what 4 parts?
1) Return Type
2) Name
3) Parameter list
4) Body
Define: Return type (of a function)
#1 data type of the value that is sent FROM the function listed first int main() --> int is the RETURN TYPE
Define: Name (of a function)
#2 Should give each function a descriptive name - in general, same rules apply as to variables for naming int main() --> main is the NAME
Define: Parameter List (of a function)
#3 List of variables that hold the values being passed TO the function int main() --> () is the parameter list (it's empty!)
Define: Body (of a function)
The set of statements that perform the function's operation.
enclosed in a set of braces
int main()
{
BODY HERE
}Define: Function Header
The line in the definition that reads int main() (the first line)
Define: Void functions (they return….)
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
void displayMessage()
{
cout << "hello from the function displayMessage. \n";
}
What part is the function header?
How would you "call" this function?Function Header: void displayMessage()
Call: displayMessage();
Fuction prototypes are also known as …
Function declarations
You must place either the function definition or the function prototype _______ all calls to the functions.
What happens if you don’t?
BEFORE
Or else the program will not compile
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";
}
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.
When a function is called, the program may send _____ into the function.
VALUES
Values sent into a function are called ___________.
arguments
Define: Parameter
a special variable that holds a value being passed into a function.
For example:
void displayValue(int num)
{
court «_space;“The value is “ «_space;num «_space;endl;
}
The variable num is the parameter.
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;
}void displayValue(int);
How would you call the function of this prototype: void displayValue(int);
displayValue(5); (this could be any integer where the argument 5 is)
What could the function body be for the following function:
void displayValue(int);
void displayValue(int num)
{
cout << "The value is " << num << endl;
}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.
Data Type.
displayValue(int x); // Error!
Call should appear as:
displayValue(x); // Correct
If you pass an argument whose TYPE is not the same as the parameter’s type, the argument will be ________ or _________ automatically.
promoted or demoted
Ex: the following function call would be truncated (because the parameter is an integer not double):
displayValue(4.7);
WARNING!
Each parameter variable in a parameter list must have a _____ _____ listed before its name.
Provide an example.
Data Type: void showSum (int num1, num2, num3) // ERROR!
void showSum (int num1, int num2, int num3) // Correct
When a function with multiple parameters is called, the arguments are passed to the parameter in ______.
order.
example: showSum(5, 10, 15); passes 5, 10, 15 in that order ….
