method

Question 1

java predefined method for finding the absolute value

Answer 1

Math.abs( any number )

Question 2

java predefined method for finding the bigger (max) value

Answer 2

Math.max(big num, small num)

Question 3

java predefined method for finding a num to the power of another num

Answer 3

Math.pow

Question 4

java predefined method for finding the smaller (min) max

Answer 4

Math.min

Question 5

java predefined method for rounding a num

Answer 5

long x = Math.round

Question 6

java predefined method for finding the square root

Answer 6

Math.sqrt

Question 7

in Math.ceil, you round to the

Answer 7

right
ex:
double num = Math.ceil (2.4); ///3.0
double num = Math.ceil(-2.4); //-2.0
double num = Math.ceil(2.0); //2.0

Question 8

in Math.floor, you round to the

Answer 8

left
ex:
double num = Math.ceil (2.4); ///2.0
double num = Math.ceil(-2.4); //-3.0
double num = Math.ceil(2.0); //2.0

Question 9

java predefined method for giving you random numbers within a certain range

Answer 9

Math.random();
ex:
print number between 1000 and 1113 inclusive
System.out.println(int) ( Math.random() * 114 + 1000 );
[we take the difference between the two numbers and add 1 to it then multiply it to Math.random(), the add the smaller value between the two]

Question 10

what can you write at the beginning of a code that uses a lot of Math. predefined methods?

Answer 10

import static java.lang.Math.*;

Question 11

T/F: in a public class, there can exist public static void main only.

Answer 11

F, we can also have a method public static void.

Question 12

T/F: in a public class, there can exist public static void main only.

Answer 12

F, we can also have a method public static void.

Question 13

T/F: You can call out a method more than once in main.

Answer 13

T,

public class testM2
3 {
4 public static void main(String args[])
5 {
6 System.out.println(“welcom”) ;
7
8 mona() ;
9
10 System.out.println(“end my program”) ;
11 mona() ;
12 }
13 public static void mona()
14 {
15 System.out.println(“inside mona “) ;
16 }

Question 14

T/F: You can name a method anything even if it defies the naming laws.

Answer 14

F, you can name it anything so long as it abides by the naming laws

Question 15

the variables in a method header are called _________

Answer 15

formal parameter

Question 16

the variables that are called out in main not metho are the ________

Answer 16

actual parameter

Question 17

T/F: the variable intialized in main must be the same in the method.

Answer 17

F, in main the variable could be called out as (a , b) and in method they would be (x, y)

Question 18

is the following correct:
public static void sum (int x, y)

Answer 18

incorrect, we have to identify the variables each time since this area isn’t an intializing space…
public static void sum (int x, int y)

Question 19

T/F: the method must be intialized inside of the main to be called out.

Answer 19

true

Question 20

a reserved word in method that destroys everything before it and returns only the thing you next to it to main.

Answer 20

return
ex:
public static int sum (int x, int y){
int s = x + y
return s ;
}

Question 21

correct the following:
public static void sum (int x, int y){
int s = x + y
return s ;
}

Answer 21

it must be int not void since the value you are going to return is int.
public static int sum (int x, int y){
int s = x + y
return s ;
}

Question 22

correct the following:
import java.util.*;
public class testMethod{
scanner console = new Scanner(System.in);
public static void main (String[] args){

Answer 22

if the scanner is written before/outside the main, we must add “static” to it.

import java.util.*;
public class testMethod{
static scanner console = new Scanner(System.in);
public static void main (String[] args){

Question 23

correct the following:
public static void main (String[] args){
System.out.println( squar(10) );
System.out.println( cube(10) );
}

public static int square(int x){
return x*x;
}

public static void cube(int x){
System.out.println( Math.pow(x, 3));
}

Answer 23

incorrection: calling out the method in print.
public static void main (String[] args){
System.out.println( squar(10) );
cube(10);
}

public static int square(int x){
return x*x;
}

public static void cube(int x){
System.out.println( Math.pow(x, 3));
}

Question 24

correct the following:
public static int methodsx(int x){
System.out.println(“**”);
return x + 5;
System.out.println(“end.”);
}

Answer 24

incorrection: adding anything after return is useless and a “unreachable statement” message would appear for you as an error.

public static int methodsx(int x){
System.out.println(“**”);
return x + 5;
}

Question 25

correct the following:
public static int (int x){
if (x > 0)
return x+ 5;
return x;
}

Answer 25

incorrecting: missing method name.

public static int meow(int x){
if (x > 0)
return x+ 5;
return x;
}

Question 26

correct the following:
public static void methodx(int x){
if ( x > 0 )
return x + 5;
}

Answer 26

incorrection (2): incorrect method type, and missing return

public static int methodx(int x){
if ( x > 0 )
return x + 5;
return x;
}

Question 27

correct the following:
public static void area (int x, y)
{
System.out.println(“area=” + (x*y));
}

Answer 27

incorrection: not adding a variable type to both variables in a parameter.

public static void area (int x, int y)
{
System.out.println(“area=” + (x*y));
}

Question 28

correct the following:
public static void main (String[] args){
area(“10”, “30”);
}

public static void area (int x, int y){
System.out.println(“area =” + (x* y);
}

Answer 28

incorrection: the variable type defined in method is int, and in main it is string in the parameter.

public static void main (String[] args){
area( 10, 30 );
}

public static void area (int x, int y){
System.out.println(“area =” + (x* y);
}

Question 29

correct the following:
public static void main(String[] args){

sum (10.6, 3);
sum (50 , 100);
sum (5 , 10.8);
}

public static void sum(double x, int y) {
System.out.println(x + y);
}

Answer 29

incorrection: the variables in the parameter in main don’t ALL match the variable type in method.

public static void main(String[] args){

sum (10.6, 3);
sum (50 , 100);
sum (5 , 10.8);
}

public static void sum(double x, double y) {
System.out.println(x + y);
}

Question 30

correct the following:
public static double power(double x, int y){
int result = Math.pow(x, y);
return result;

System.out.println(“completed’);
}

Answer 30

public static double power(double x, int y){
double result = Math.pow(x, y);
return result;
}

Question 31

correct the following:
public static void main(String args[]){
int a = 4;
int b = 2;
System.out.println( power(a,b) ));
}

}

Question 32

this. method is used when…

Answer 32

intializing and the name of the object is the same as the attribute (ex: this.name = name;)

Question 33

if there is a line under an attribute in a UML then that means that we need to intialize it as….
(ex: + numOfFemale: int is one of the attributes of class trainee. )

Answer 33

public static int numOfFemale;

Question 34

why do we use getters and setters?

Answer 34

we create a getter so that we can get a private attribute.