Chapter 2 Writing Sample Programs

Question 1

What are the 6 steps in the process of creating a program?

Answer 1

1. Analyze the problem
2. Determine Specifications
3. Create a design
4. Implement the design
5. Test/Debug the program
6. Maintain the program

Question 2

What are some standards that Identifiers (Names) must follow when programming?

Answer 2

The must all begin with a letter or and underscore character, and they can be followed by any sequence of letters or numbers. There can be no spaces in these names.

Question 3

What are the fragments of program code that produce or calculate new data values?

Answer 3

Expressions

Question 4

What are strings?

Answer 4

Textual Data

Question 5

A simple identifier can also be an expression. We use identifiers as variables to give names to values

Answer 5

ex:
»> X=5

Question 6

T or F
A variable doesn’t need to be assigned a value before it is used within a program

Answer 6

False. A variable must be defined for it to have an effect. If it is not you will receive a name error.

Question 7

T or F
Spaces are irrelevant within an expression

Answer 7

True. While spaces won’t effect if your code works or not, spaces can make a difference in how easily you can read an expression.

Question 8

Give an example of Concatenation is.

Answer 8

Concatenation is the combining of strings (adding)

EX:
»> “Bat” + “Man”

Question 9

What is a bare print?

Answer 9

A bare print has no parameters, so it produces a blank line of output. “\n”

Question 10

What would the following function do?

print ( “The answer is “, end=” “ )
print (3+4)

Answer 10

The function would print ‘ The answer is 7 ‘
The end=” “ allows for the output from the second statement to be placed there.

Question 11

Give an example of an assignment statement.

Answer 11

identifier= expression
=
Name = Ashlyn

Question 12

T or F
A variable can only be assigned a value once.

Answer 12

False! A variable can be redefined as much as you want to change it. The variable will take the values that was assigned most recently. Variables are called variables because they are ( can ) constantly changing.

Question 13

What is a name for the process of automatic memory management?

Answer 13

Garbage Collecting

Question 14

How can you allow a variable to be based off of an input?

Answer 14

= input()

Question 15

How can you allow for input to be entered into a variable if you need numbers?

Answer 15

= eval (input ())

Question 16

T or F
the eval (input) function is extremely powerful and safe to use in all forms of programming!

Answer 16

False. It can be extremely dangerous if the input ability falls into the hands of an experienced hacker who would be able to code inject.

Question 17

What is Code Injecting?

Answer 17

injecting malicious code into the running program.

Question 18

What’s an alternative form of the assignment statement?

Answer 18

Simultaneous Assignment, this allows us to calculate several values all at the same time.
EX:
<var>, = , </var>

Question 19

What’s the most effective way to swap the values of variables?

Answer 19

Creating a temp variable and doing a three way swap.
temp = X
X = Y
Y = temp

Question 20

What’s another way you can swap the values of variables?

Answer 20

X, Y = Y, X
bc the assignment is simultaneous it avoids wiping out on of the original values so this method works.

Question 21

What is the simplest for of a loop?

Answer 21

A definite loop.
EX:
for i in range (10)
-Counted loop

Question 22

True or False
The best way to write a program is to type in some code and then debug it until it works

Answer 22

False

Question 23

Given the following line of python code, match each part (on the left) with the descriptive term for that part (on the right):

x = x * 3.9

X
*
3.9

Answer 23

X- Variable
*- operator
3.9- Literal

Question 24

Fragments of code that produce or calculate new data values are called:

Answer 24

Expressions