2. Writing Simple Programs

Question 1

True or False

The best way to write a program is to immediately type in some code and then debug it until it works.

Answer 1

False

We need a systematic approach.

Question 2

True or False

An algorithm can be written without using a programming language.

Answer 2

True

Pseudocode is just precise English that describes what a program does. It is meant to communicate algorithms without all the extra mental overhead of getting the details right in any particular programming language.

Question 3

True or False

Programs no longer require modification after they are written and debugged.

Answer 3

False

Most programs are never really finished; they keep evolving over years of use.

Question 4

True or False

Python identifiers must start with a letter or underscore.

Answer 4

True

Every identifier must begin with a letter or underscore which may be followed by any sequence of letters, digits, or underscores. This implies that a single identifier cannot contain any spaces.

Question 5

True or False

Keywords make good variable names.

Answer 5

False

These names are called reserved words or keywords and cannot be used as ordinary identifiers.

Question 6

True or False

Expressions are built from literals, variables, and operators.

Answer 6

True

Expressions are the fragments of a program that produce data. An expression can be composed of literals, variables and operators.

Question 7

True or False

In Python, x = x + 1 is a legal statement.

Answer 7

True

Question 8

True or False

Python does not allow the input of multiple values with a single statement.

Answer 8

False

Python also allows simultaneous assignment, which is useful for getting multiple input values with a single prompt.

, , … = , , …,

Question 9

True or False

A counted loop is designed to iterate a specific number of times.

Answer 9

True

One important use of a for statement is in implementing a counted loop, which is a loop designed specifically for the purpose of repeating some portion of the program a specific number of times. A counted loop in Python is created by using the built-in range function to produce a suitably sized sequence of numbers.

for <var> in :
</var>

Question 10

True or False

In a flowchart, diamonds are used to show statement sequences, and rectangles are used for decision points.

Answer 10

False

Rectangles are used to show statement sequences, and diamonds are used for decision points.

Question 11

Which of the following is not a step in the software development process?

a) specification
b) testing/Debugging
c) fee setting
d) maintenance

Answer 11

c) fee setting

Question 12

The process of describing exactly what a computer program will do to solve a problem is called

a) design
b) implementation
c) programming
d) specification

Answer 12

d) specification

Program Specification: Deciding exactly what the program will do.

Question 13

Which of the following is not a legal identifier?

a) spam
b) spAm
c) 2spam
d) spam 4U

Answer 13

d) spam 4U

Question 14

Which of the following are not used in expressions?

a) variables
b) statements
c) operators
d) literals

Answer 14

b) statements

statements are built from identifiers and expressions.

Question 15

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

a) identifiers
b) expressions
c) productive clauses
d) assignment statements

Answer 15

b) expressions

Expressions are the fragments of a program that produce data.

Question 16

Which of the following is not a part of the IPO pattern?

a) input
b) program
c) process
d) output

Answer 16

b) program

IPO : input, process, output pattern

Question 17

The template for in range ( ) describes

a) a general for loop
b) an assignment statement
c) a flowchart
d) a counted loop

Answer 17

d) a counted loop

One important use of a for statement is in implementing a counted loop, which is a loop designed specifically for the purpose of repeating some portion of the program a specific number of times. A counted loop in Python is created by using the built-in range function to produce a suitably sized sequence of numbers.

Question 18

Which of the following is the most accurate model of assignment in Python?

a) sticky-note
b) variable-as-box
c) simultaneous
d) plastic-scale

Answer 18

a) sticky-note

Assigning a variable is like putting one of those little yellow sticky notes on the value and saying, “this is x.”

Question 19

In Python, getting user input is done with a special expression called

a) for
b) read
c) simultaneous assignment
d) input

Answer 19

d) input

The eval function can be used to evaluate user input.

eval(input())