Chapter 3 Conditions

Question 1

What is a good general practice to add to ending braces?

Answer 1

Add a comment to denote what the end brace is used for

Question 2

What are three common operators found in Boolean algebra and what values do they manipulate?

Answer 2

“And”, “or”, and “not” are used to manipulate the values “true” and “false”.

Question 3

What are three common operators found in Boolean algebra?

Answer 3

And
Or
Not

Question 4

Who is Boolean algebra named after?

Answer 4

George Boole, a nineteenth-century English mathematician.

Question 5

When using the “and” operator, what is required for the compound condition (entire expression) to be true?

Answer 5

Both sides of the “and” operator must be true

Ex.: 3==3 and 4==4 is true

Question 6

When using the “or” operator, what is required for the compound condition (entire expression) to be true?

Answer 6

At least one side of the “or” operator must be true

Ex.: 3==3 or 3==4 is true

Question 7

How does the C programming language treat all nonzero and zero values?

Answer 7

All nonzero values are treated as true while all zero values are treated as false.

Question 8

What character set represents the “and” Boolean operator?

Answer 8

&& (two ampersands)

Question 9

What library is the “isdigit ()” function a part of?

Answer 9

The library.

Question 10

What library is the “isdigit ()” function a part of?

Question 11

What is the “switch (x)” structure used for?

Answer 11

When programmers want to evaluate a user’s response to a specific set of choices.

Ex.: When a user selects an item from a menu.

Question 12

What are three common operators found in Boolean algebra?

Answer 12

And
Or
Not

Question 13

Who is Boolean algebra named after?

Answer 13

George Boole, a nineteenth-century English mathematician.

Question 14

When using the “and” operator, what is required for the compound condition (entire expression) to be true?

Answer 14

Both sides of the “and” operator must be true

Ex.: 3==3 and 4==4 is true

Question 15

What is the “srand ()” function used for?

Answer 15

The “srand ()” function seeds a variable into the rand () function to dictate the random number generator algorithm.

Question 16

What is commonly paired with the srand () function to produce a psuedorandom number generator so that numbers are as random as possible?

Answer 16

The “time (NULL)” function.

Ex.: srand (time (NULL))

Question 17

What character set represents the “and” Boolean operator?

Answer 17

&& (two ampersands)

Question 18

What character set represents the “or” Boolean operator?

Answer 18

|| (two pipe characters)

Question 19

What library is the “isdigit ()” function a part of?

Answer 19

The ctype.h library.

Question 20

What is the “isdigit ()” function used for?

Answer 20

A tool used to validate whether the user entered either digits or non-digit characters.

The “isdigit ()” function returns “true” if its passed-in value evaluates to a digit, and “false (0)” if not.

Question 21

What is the “switch (x)” structure used for?

Answer 21

When programmers want to evaluate a user’s response to a specific set of choices.

Ex.: When a user selects an item from a menu.

Question 22

What keyword is used to stop the processing of each “case” statement after the appropriate “case” statement is matched?

Answer 22

break

Question 23

What function is used to generate a random number and what operator is it commonly paired with?

Answer 23

The “rand ()” function. It is paired with the modulus (%) operator:

(rand () % 10) + 1 This will generate a random number between 0 and 9 and then add 1 so the new range will be 1 and 10.

Question 24

What is a disadvantage of the “rand ()” function?

Answer 24

The “rand ()” function generates the same sequence of random numbers repeatedly. It cannot generate another random number without the use of the “srand ()” function.

Question 25

What is the “srand ()” function used for?

Answer 25

The “srand ()” function tells the “rand()” function to produce a different random number every time it is executed.

Question 26

What is commonly paired with the srand () function to produce a psuedorandom number generator so that numbers are as random as possible?

Answer 26

The “time (NULL)” function.

Ex.: srand (time (NULL))

Question 27

Conditions are implemented using what type of structure?

Answer 27

“if” structures which contains an expression enclosed within parenthesis