lec 5

Question 1

What Java class provides methods for performing mathematical operations?

Answer 1

Math class

Question 2

What does Math.pow(2, 3) return?

Answer 2

8.0

Question 3

How do you calculate the square root of a number in Java?

Answer 3

Math.sqrt(x)

Question 4

What does Math.sqrt(10.5) return?

Answer 4

3.24

Question 5

How do you find the maximum value between two numbers?

Answer 5

Math.max(x, y)

Question 6

What does Math.max(5,10) return?

Answer 6

10

Question 7

How do you find the minimum value between two numbers?

Answer 7

Math.min(x, y)

Question 8

What does Math.min(2.5, 3.6) return?

Answer 8

2.5

Question 9

How do you get the absolute (positive) value of a number?

Answer 9

Math.abs(x)

Question 10

What does Math.abs(-2.1) return?

Answer 10

2.1

Question 11

What does Math.random() return?

Answer 11

A random double between 0.0 (inclusive) and 1.0 (exclusive)

Question 12

How do you generate a random integer between 0 and 9?

Answer 12

(int)(Math.random() * 10)

Question 13

What does 50 + (int)(Math.random() * 50) return?

Answer 13

A random integer between 50 and 99

Question 14

How do you generate a random integer between 0 and 100?

Answer 14

int)(Math.random() * 101)

Question 15

Fill in the blank: Math._______(x, y); to get the highest value between x and y

Answer 15

Math.max(x, y);

Question 16

Fill in the blank: Math.________(x); to find the square root of x.

Answer 16

Math.sqrt(x);

Question 17

Fill in the blank: Math._______; to return a random number between 0 and 1

Answer 17

Math.random();

Question 18

How do you declare a char variable in Java?

Answer 18

char letter = ‘A’;

Question 19

What happens when you increment a char variable in Java?

Answer 19

It moves to the next Unicode character.

Question 20

What does char ch = ‘a’; System.out.println(++ch); output?

Answer 20

b

Question 21

What is the ASCII code for ‘0’?

Answer 21

48

Question 22

What is the Unicode value of ‘A’?

Answer 22

\u0041

Question 23

What is the ASCII code for lowercase ‘z’?

Answer 23

122

Question 24

What is the numeric value of char c = ‘a’; when cast to int?

Answer 24

97

Question 25

What is the output of char c = 97; System.out.println(c);?

Answer 25

a

Question 26

How do you declare a string variable?

Answer 26

String message = "Hello";

Question 27

What class does Java use to handle strings?

Answer 27

String class

Question 28

How do you find the length of a string in Java?

Answer 28

stringVariable.length()

Question 29

What does System.out.println("Hello".length()); return?

Answer 29

5

Question 30

How do you get the first character of a string?

Answer 30

stringVariable.charAt(0);