Chap. 1 eloquent javascript

Question 1

(100 + 4) * 11

Answer 1

1,144

Question 2

What character to use to get a space at “And”

“This is the first line And this is the second”

Answer 2

\n

Question 3

write out:

“A newline character is written like “\n”.”

as code

Answer 3

“A newline character is written like "\n”.”

Question 4

The following returns?

console.log(half of 100 is ${100 / 2} );

Answer 4

‘Half of 100 is 50’

Question 5

${} is called

Answer 5

template literal

Question 6

The following returns:

console.log(- (10 - 2))

Answer 6

-8

Question 7

console. log(typeof 4.5)

console. log(typeof “x”)

Answer 7

// → number
// → string

Question 8

console.log(3 > 2)

Answer 8

// → true

Question 9

console.log(3 < 2)

Answer 9

// → false

Question 10

console.log(“Itchy” != “Scratchy”)

Answer 10

// → true

Question 11

console.log(“Apple” == “Orange”)

Answer 11

// → false

Question 12

console.log(NaN == NaN)

Answer 12

// → false

Question 13

> =

Answer 13

greater than or equal too

Question 14

<=

Answer 14

less than or equal too

Question 15

!=

Answer 15

not equal too

Question 16

= =

Answer 16

equal too

Question 17

console.log(true && false)

Answer 17

// → false

Question 18

console.log(true && true)

Answer 18

// → true

Question 19

console.log(false || true)

Answer 19

// → true

Question 20

console.log(false || false)

Answer 20

// → false

Question 21

!true

Answer 21

False

Question 22

!False

Answer 22

True

Question 23

console.log(true ? 1 : 2);

Answer 23

// → 1

Question 24

console.log(false ? 1 : 2);

Answer 24

// → 2

Question 25

There are two special values, written ____ and ____, that are used to denote the absence of a meaningful value

Answer 25

Null undefined

Question 26

console.log(8 * null)

Answer 26

// → 0

Question 27

console.log("5" - 1)

Answer 27

// → 4

Question 28

console.log("5" + 1)

Answer 28

// → 51

Question 29

console.log("five" * 2)

Answer 29

// → NaN

Question 30

console.log(false == 0)

Answer 30

// → true

Question 31

console.log(true == 0);

Answer 31

// → false

Question 32

When something that doesn’t map to a number in an obvious way (such as "five" or undefined) is converted to a number, you get the value

Answer 32

NaN

Question 33

console.log(null == undefined);

Answer 33

// → true

Question 34

console.log(null == 0);

Answer 34

// → false

Question 35

console.log(" " == false);

Answer 35

// → true

Question 36

console.log(" " === false);

Answer 36

// → false

Question 37

console.log(null || "user")

Answer 37

// → user

Question 38

console.log("Agnes" || "user")

Answer 38

// → Agnes

Question 39

console.log(NAN || "user")

Answer 39

reference error

Question 40

The rules for converting strings and numbers to Boolean values state that 0, NaN, and the empty string ("") count as

Answer 40

false

Question 41

console.log(0 || -1)

Answer 41

-1

Question 42

console.log(0 && -1)

Answer 42

0

Question 43

console.log(-1 && 0)

Answer 43

0

Question 44

console.log(-1 || 0)

Answer 44

-1

Question 45

console.log(1 - 2 + 1)

Answer 45

0

Question 46

console.log(NaN == NaN)

Answer 46

flase

Question 47

There is only one value in JavaScript that is not equal to itself, and that is ______

Answer 47

NaN

Question 48

console.log(true !& true)

Answer 48

syntax error

Question 49

``` var a = 3; var b = -2; console.log(!(a > 0 || b > 0)); ```

Answer 49

// false

Question 50

If expr1 can be converted to true, returns expr2; else, returns expr1.

Answer 50

&& operator

Question 51

If expr1 can be converted to true, returns expr1; else, returns expr2.

Answer 51

|| operator

Question 52

Examples of expressions that can be converted to false are:

Answer 52

``` null; NaN; 0; empty string ("" or '' or ``); undefined.` ```

Question 53

console.log(true || false && false); why?

Answer 53

// returns true, because && is executed first

Question 54

console.log((true || false) && false); why?

Answer 54

// returns false, because operator precedence cannot apply

Question 55

n3 = !''

Answer 55

// !f returns true

Question 56

n4 = !'Cat'

Answer 56

// !t returns false

Question 57

true || true

Answer 57

//true

Question 58

o2 = false || true

Answer 58

// true

Question 59

o3 = true || false

Answer 59

// true

Question 60

o4 = false || (3 == 4)

Answer 60

// false

Question 61

o5 = 'Cat' || 'Dog'

Answer 61

//"Cat"

Question 62

o6 = false || 'Cat'

Answer 62

//"Cat"

Question 63

o7 = 'Cat' || false

Answer 63

// "Cat"

Question 64

o8 = '' || false

Answer 64

// false

Question 65

o9 = false || ''

Answer 65

// ""

Question 66

o10 = false || varObject /

Answer 66

// varObject

Question 67

bCondition1 && bCondition2 | is always equal to:

Answer 67

!(!bCondition1 || !bCondition2)

Question 68

bCondition1 || bCondition2 | is always equal to:

Answer 68

!(!bCondition1 && !bCondition2)

Question 69

!!bCondition | is always equal to:

Answer 69

bCondition

Question 70

console. log(true && true); console. log(true && false); console. log(false && true); console. log(false && false);

Answer 70

true false false false

Question 71

console. log(true || true); console. log(true || false); console. log(false || true); console. log(false || false);

Answer 71

true true true false

Question 72

This operator is frequently used as an alternative to an if...else statement.

Answer 72

Conditional (ternary) operator