Unit 2

Question 1

What is a procedure?

Answer 1

A procedure takes in inputs, does some processing, and produces outputs.

A procedure is a way to package code so it can be reused with different inputs. Also known as functions, procedures enable you to abstract code from its inputs.

def ():

Question 2

What is control in programming?

Answer 2

Control is a way to have the computer execute different instructions depending on the data rather than just executing instructions one after the other.

Question 3

What do “if statements” allow you to do?

Answer 3

“if statements” allow you to write code that executes differently depending on the test expression.

if :

Question 4

What do “while loops” allow you to do?

Answer 4

“while loops” provide a convenient way to repeat the same operation many times.

Question 5

What is procedural abstraction?

Answer 5

Procedural abstraction is a way to write code one time that works on a wide range of different data values. By turning code into a procedure, you can use the same code over and over with different inputs to produce different outputs.

Question 6

How to you make a procedure produce outputs with Python?

Answer 6

Producing outputs finishes a procedure. To do this, the return statement is used. A return statement can have any number of expressions. The values of these expressions are the out puts of the procedure.

return , , . . .

Question 7

How does a return statements with no expression behave?

Answer 7

A return statement with no expressions means that the procedure produces no output. This is useful for certain situations, such as where when the procedure is used for the effect from the operations rather than the output produced by the procedure itself.

Question 8

In what way can procedures be thought of as mathematical functions?

Answer 8

Think of procedures as something that maps inputs to outputs. This is why procedures are often referred to as functions.

Question 9

Why are procedures an important concept?

Answer 9

Procedures are a very important concept and the core of programming is breaking problems into procedures and implementing those procedures.

Question 10

What does code need to be able to do to behave differently based on changing inputs?

Answer 10

To make decisions, code needs to be able to make comparisons, which will give your code a way to test inputs and decide what to do.

Question 11

What operators does Python use for making comparisons?

Answer 11

Greater than
= Greater than or equal to
== Equal to
!= Not equal to

Question 12

What syntax is used to make comparisons with Python and what is the output?

Answer 12

Pythons operators work on numbers, for example:

The output of a comparison is a Boolean: True or False

Question 13

What clause to the “if statement” can be used to provide an alternative block of code to execute if the test expression is false?

Answer 13

The “else” clause can be used to execute an alternative block of code if the “if statement’s” test expression returns false.

Question 14

What is the test expression of an “if statement”?

Answer 14

The test expression determines whether to execute the block inside the if statement or the block inside the else statement.

The test expression is a statement that is evaluated by the code. The procedure executes different code based on the different outputs of the evaluation of the truth statement.

Question 15

What is the “or expression”? How does it operate?

Answer 15

The “or expression” gives the logical or (disjunction) or two operands. If the first expression evaluates to True, the value is True and the second expression is not evaluated. If the value of the expression evaluates to False then the value of the or is the value of the second expression.

or

Question 16

What is a loop? What is the “while loop”?

Answer 16

Loops are a way of executing a selection of code over and over.

The “while loop” is a common loop and similar to the “if statement” in that it evaluates a test expression and changes its action based on certain outputs of the evaluation of the test expression.

while :

Question 17

How does a “while loop” operate?

Answer 17

If the test expression for a while loop evaluates to True, the block is executed. Then the loop returns to reevaluate the test expression and see if the evaluation output has changed based on any changes that have occurred since or because of the execution of the previous loop. If it still evaluates to true, the block is again executed, and again returns to reevaluate the test expression until the the evaluation returns False. Once it returns False, execution jumps to the next statemetnt

Question 18

What does “break” let you do?

Answer 18

Break gives you a way to break out of a loop, even if the test condition is true. The typical structure of a loop with a break looks like:

while :
<code>
if :
break # stop executing the while loop</code>

The break statement will jump out of the loop the the </code>

Question 19

What is multiple assignment?

Answer 19

Multiple assignment is where you assign multiple values on the left side of an assignment statement. With multiple assignment, you can assign any number of names separated by commas, an equal sign and then any matching number of expressions separated by commas. The first name is assigned to the first expression and so on.

, , . . . = , , . . .