using classes and objects

Question 1

what is the println method

Answer 1

is a service provided by the system.out objects

Question 2

how we created a scanner object

Answer 2

using the new operator

Question 3

an object variable does not contain the variable itself true or false

Answer 3

true

it holds the address of an object

Question 4

after the new operator creates an object

Answer 4

true

Question 5

if we change the string of string object will be right

true or false

Answer 5

false

string object is immutable

Question 6

what is alise

Answer 6

aliasing refers to a situation where two different expressions or symbols refer to the same object./

Question 7

what is the “charAt(int index)”

Answer 7

Returns the char value at the specified index.

Question 8

what is the “compareTo(String anotherString)”

Answer 8

int

Compares two strings lexicographically.

Question 9

compareToIgnoreCase(String str)

Answer 9

Compares two strings lexicographically, ignoring case differences.

Question 10

length()

Answer 10

Returns the length of this string.

Question 11

toLowerCase()

Answer 11

Converts all of the characters in this String to lower case using the rules of the default locale.

Question 12

toUpperCase()

Answer 12

Converts all of the characters in this String to upper case using the rules of the default locale.

Question 13

what is the explanation of compere to

Answer 13

The result is a negative integer if this String object lexicographically precedes the argument string. The result is a positive integer if this String object lexicographically follows the argument string. The result is zero if the strings are equal;

Question 14

math rondom

Answer 14

random from [0,1[

Question 15

(int)((math.random()*10)+10 )

Answer 15

0-19

Question 16

(int) math.random()*10

Answer 16

0
0
0

Question 17

gen.nextInt(5)

Answer 17

0-4

Question 18

Math.abs()

Answer 18

int abs1 = Math.abs(10); // abs1 = 10

int abs2 = Math.abs(-20); // abs2 = 20

Question 19

Math.ceil()

Answer 19

double ceil = Math.ceil(7.343); // ceil = 8.0

Question 20

Math.floor()

Answer 20

double floor = Math.floor(7.343); // floor = 7.0

Question 21

Math.min()

Answer 21

int min = Math.min(10, 20);

10

Question 22

Math.max()

Answer 22

int max = Math.max(10, 20);

Question 23

Math.pow()

Answer 23

double pow2 = Math.pow(2,2);
System.out.println(“pow2 = “ + pow2);

double pow8 = Math.pow(2,8);
System.out.println(“pow8 = “ + pow8);

Question 24

Math.sqrt()

Answer 24

double sqrt4 = Math.sqrt(4);
System.out.println(“sqrt4 = “ + sqrt4);

double sqrt9 = Math.sqrt(9);
System.out.println(“sqrt9 = “ + sqrt9);