functions

Question 1

a group of statements that exist within a program for the purpose of performing a specific task is a …….

Answer 1

function

Question 2

a design technique that helps to reduce the duplication of code within a program is ……..

Answer 2

code reuse

Question 3

the first line of a function is known as the ………

Answer 3

header

Question 4

you ……. a function to execute it

Answer 4

call

Question 5

a design technique that programmers use to break down an algorithm into functions is known as …….

Answer 5

top-down design

Question 6

a ……. is a diagram that gives a visual representation of the relationships between functions in a program

Answer 6

hierarchy chart

Question 7

a ……… is a variable that is created inside a function

Answer 7

local variable

Question 8

a ……… is the part of a program in which a variable may be accessed

Answer 8

scope

Question 9

an ………. is a piece of data that is sent into a function

Answer 9

argument

Question 10

a ………… is a special variable that receives a piece of data when a function is called

Answer 10

parameter

Question 11

a variable that is visible to every function in a program file is a ……..

Answer 11

global variable

Question 12

when possible you should avoid using …….. variables in a program

Answer 12

global

Question 13

library function

Answer 13

this is a pre-written function that is built into a programming language

Question 14

‘random()’

Answer 14

this standard library function returns a random integer within a specified range of values
and/or
this standard library function returns a random floating-point number in the range of 0.0 up to but not including 1.0

Question 15

‘uniform()’

Answer 15

this standard library function returns a random floating-point number within a specified range of values

Question 16

‘return’

Answer 16

this statement causes a function to end and sends a value back to the part of the program that called the function

Question 17

datagram chart

Answer 17

this is a design tool that describes the input, processing and output of a function

Question 18

Boolean

Answer 18

this type of function returns true or false

Question 19

differentiate

Answer 19

this is a maths module function

Question 20

How do functions help you to reuse code in a program?

Answer 20

They let you perform the same operations over and over without having to retype every line of the implementation.

Question 21

Name and describe the two parts of a function definition.

Answer 21

The header is the first line of a function definition and it defines the name and any parameter variables. The body defines what the function does.

Question 22

When a function is executing, what happens when the end of the function block is reached?

Answer 22

At the end of the function block, the program goes back to the place where the function was called and continues executing statements from that point. Using the standard nomenclature, we say that control returns to the point that the function was called.

Question 23

What is a local variable? What statements are able to access a local variable?

Answer 23

A local variable is a variable that is defined inside a function block without the global keyword. The only statements that are able to access a local variable are those that come after it within the same function block.

Question 24

What is a local variable’s scope?

Answer 24

everywhere below the point the variable is defined that is within the same function as the variable

Question 25

Why do global variables make a program difficult to debug?

Answer 25

Global variables make programs difficult to debug because when you find that you’re getting the wrong value in one, it’s hard to narrow down where the error is coming from.

Question 26

What library function would you use to select a random number from;
0, 5, 10, 15, 20, 25, 30 ?

Answer 26

you would use the 'randrange()' function from the 'random' module
specifically 'random.randrange(0, 31, 5)'

Question 27

What statement do you have in a value-returning function?

Answer 27

The difference between a void function and a value-returning function is the existence of a ‘return’ statement in a value-returning function. This statement sends some value back to the point in the program where the function was called.

Question 28

What three things are listed on an IPO chart?

Answer 28

Input: a brief description of the parameters of the function

Processing: a brief description of what the function is supposed to do

Output: a brief description of what value(s) the function returns

Note that the input and/or output columns may be empty, depending on what you want the function to do.

Question 29

What is a Boolean function?

Answer 29

one that returns either ‘True’ or ‘False’

Question 30

What are the advantages of breaking a large program into modules?

Answer 30

1. If you’ve defined a bunch of functions, then by putting those in separate module files you won’t have to scroll past them to see the mainline logic of your program.
2. Splitting a program into modules where each module is a collection of related functions makes it easier to reuse code between programs. You may find that you have several programs that all need to perform the same astronomy calculations (you’re an astronomer in this example), so the module you’ve created with a bunch of astronomy functions will be useful to import into each of them.
3. Once you’ve used a module for a while, you can be pretty sure you’ll have worked out all the bugs in it. So it reduces the possibility of bugs.
4. When working in a group, it’s both easier and more useful for each coder to work on a single module of related functions than on some random selection of functions/ sections of code.

Question 31

What is a function?

Answer 31

A function is a group of statements that exist within a program for the purpose of performing a specific task.

Question 32

What is an argument?

Answer 32

any piece of data that is passed into a function when the function is called

Question 33

What is a parameter?

Answer 33

a variable that receives an argument that is passed into a function