JAVA basics

Beschreibung

Introductory JAVA concepts
Joseph Jimenez
Quiz von Joseph Jimenez, aktualisiert more than 1 year ago
Joseph Jimenez
Erstellt von Joseph Jimenez vor mehr als 7 Jahre
165
1

Zusammenfassung der Ressource

Frage 1

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System.out.println or next.Int( ) or close( ) are examples of:
Antworten
  • syntax
  • variable
  • method
  • object

Frage 2

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In the following sample code, how do you best describe the "Scanner": public class squares { public static void main(String[] args) { java.util.Scanner scanner = new java.util.Scanner(System.in); int num = 0; System.out.print("Please enter a number: "); num = scanner.nextInt(); scanner.close();
Antworten
  • statement
  • method
  • object
  • argument

Frage 3

Frage
In the sample code below, what best describes num ? public static void main(String[] args) { java.util.Scanner scanner = new java.util.Scanner(System.in); int num = 0; int result = 0; System.out.print("Please enter a number: "); num = scanner.nextInt(); result = num * num; scanner.close(); } }
Antworten
  • string
  • statement
  • variable
  • object

Frage 4

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All is (are) true of pseudocode except:
Antworten
  • comments that are understood by people
  • recognized by the compiler
  • a tool programmers use when creating a model of the program

Frage 5

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string literals. – char literals are enclosed in [blank_start]single[blank_end] quotes. - [blank_start]String[blank_end] literals are enclosed in double quotes
Antworten
  • single
  • String

Frage 6

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How do you assign a variable?
Antworten
  • use an = sign
  • In order to store a value in a variable, an assignment statement must be used
  • Both are correct

Frage 7

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This program asks to simply input a word or "string" and the output is the first character of the word (so an input of agents, the program's output is "a") java.util.Scanner scanner = [blank_start]new java.util.Scanner(System.in);[blank_end] [blank_start]System.out.print[blank_end]("Enter a character: "); char inputChar = [blank_start]scanner.next().charAt(0);[blank_end] System.out.println("You have entered: "+inputChar); [blank_start]scanner.close();[blank_end]
Antworten
  • new java.util.Scanner(System.in);
  • System.out.print
  • scanner.next().charAt(0);
  • scanner.close();

Frage 8

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What is wrong with the following code: System.out.println("The quick brown fox" + "jumped over the \n" "slow moving hen.");
Antworten
  • there are extra " " between \n and slow
  • use of the "+" is not correct
  • nothing is wrong with the code and should print "jump over the \n slow moving hen

Frage 9

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which is NOT a valid statement
Antworten
  • */comment 3/*
  • //comment 1
  • /**comment 4*/

Frage 10

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Which of the following will fix the code below: final int x = 22, y = 4; y += x; System.out.println("x = " + x + ", y = " + y);
Antworten
  • change y+=x; to y = y + x
  • remove "final" because this makes the "int x" a constant
  • nothing is wrong with the code

Frage 11

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How can you output quotation marks around green ("green") in the System.out.println() method:
Antworten
  • System.out.println("\green\")
  • System.out.println(\"green\")
  • System.out.println(\\"green"\\)

Frage 12

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In the JAVA language, fill in what best coincides with the given term Classes: [blank_start]PascalCase[blank_end] [blank_start]Methods/Variables[blank_end]: camelCase [blank_start]Constants[blank_end]: CAPS_UNDERSCORE
Antworten
  • PascalCase
  • Methods/Variables
  • Constants

Frage 13

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How do you define a method?
Antworten
  • public.java.util.scanner = scanner()
  • public returnType methodName(arg1Type, arg2Type,...) { }
  • import java util.*;

Frage 14

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In the following code, System.out.println(num) is an example of: double num = 5.4; System.out.println(num); num = 0.0;
Antworten
  • class method
  • value returning method
  • void method

Frage 15

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If method A calls method B, and method B calls method C, and method C calls method D, when method D finishes, what happens?
Antworten
  • the program terminates
  • control is returned to C
  • control is returned to A

Frage 16

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When an argument is passed to a method:
Antworten
  • values may not be passed to the method
  • its value is copied into the method's parameter variable
  • its value may not be changed within the call method

Frage 17

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In the following code, Integer.parseInt(str), is an example of: int num; string str = "555"; num = Integer.parseInt(str) + 5;
Antworten
  • void method
  • value returning method
  • complex method

Frage 18

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If chr is a character variable, which of the following if statements is written correctly?
Antworten
  • if(char = 'a')
  • if (char == 'a')
  • If(char=="a")

Frage 19

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[blank_start]Short-circuit evaluation[blank_end] works like this: If the expression on the left side of the && operator is false, the expression the right side will not be checked.
Antworten
  • Short-circuit evaluation

Frage 20

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To do a case insensitive compare which of the following could be used to test the equality of two strings, str1 and str2?
Antworten
  • str1.equalsIgnoreCase(str2)
  • str1.compareToIgnoreCase(str2) == 0
  • Both

Frage 21

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What would be the value of x after the following statements were executed? int x = 10; switch (x) { case 10: x += 15; case 12: x -= 5; break; default: x *= 3; }
Antworten
  • 20
  • 30
  • 15

Frage 22

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What will be displayed to the screen with the following statements? System.out.print("$%,.4f", 4452.34246);
Antworten
  • $4,452.34246
  • 4452.34246

Frage 23

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What will be the value of x after the following code is executed? If the code has any kind of syntax error, please type in the answer “error”. int x = 10 if (x>5) { x /= 10; } if (x<5) { x += 5; } if (x > 10) { x -=4; } else { x+=4; }
Antworten
  • 10
  • 0
  • 12

Frage 24

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An if statement's alternative path is implemented with _______.
Antworten
  • switch
  • else
  • if

Frage 25

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The part of a method that is a collection of statements that are performed when the method is executed is called the method _______.
Antworten
  • body
  • arguments

Frage 26

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When a primitive data type argument is passed to a method, it is passed by _______.
Antworten
  • reference
  • value

Frage 27

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When an object, such as a String, is passed as an argument, it is passed by
Antworten
  • value
  • reference

Frage 28

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What will be the values of x and y as a result of the following code? int x = 25, y = 8; x += y++;
Antworten
  • x = 33; y = 9
  • x=34; y = 9

Frage 29

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What will be printed after the following code is executed? for (int number = 5; number <= 15; number +=3) System.out.print(number + ", ");
Antworten
  • 5, 8, 11, 14, 17
  • 5, 8, 11, 14

Frage 30

Frage
UML diagrams does contain
Antworten
  • field names
  • object names

Frage 31

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Unified Modeling Language which is used in object oriented software engineering.
Antworten
  • using the private access specifier on the class methods
  • using the private access specifier on the class fields

Frage 32

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You should not define a class field that is dependent upon the values of other class fields:
Antworten
  • in order to avoid having stale data
  • in order to keep it current

Frage 33

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Instance methods do not have this key word in their headers:
Antworten
  • public
  • protected
  • static

Frage 34

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It is common practice to use a ________ variable as a size declarator
Antworten
  • reference
  • final

Frage 35

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What will be the value of x[8] after the following code has been executed? final int SUB = 12; int[] x = new int[SUB]; int y = 100; for(int i = 0; i < SUB; i++) { x[i] = y; y += 10; }
Antworten
  • 200
  • 170
  • 180

Frage 36

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Java performs ________, which means that it does not allow a statement to use a subscript that is outside the range of valid subscripts for the array.
Antworten
  • array bounds checking
  • scope resolution binding

Frage 37

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What will be the results of the following code? final int ARRAY_SIZE = 5; double[] x = new double[ARRAY_SIZE]; for(int i = 1; i <= ARRAY_SIZE; i++) { x[i] = 10.0; }
Antworten
  • compilation error will occur
  • An error will occur when the program runs

Frage 38

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What would be the results of the following code? int[] x = { 55, 33, 88, 22, 99, 11, 44, 66, 77 }; int a = 10; if(x[2] > x[5]) a = 5; else a = 8;
Antworten
  • a=5
  • a=8

Frage 39

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What would be the results of the following code? int[] array1 = new int[25]; … // Code that will put values in array1 int value = array1[0]; for (int a = 1; a < array1.length; a++) { if (array1[a] < value) value = array1[a]; }
Antworten
  • Value contains the highest value in array1.
  • Value contains the lowest value in array1

Frage 40

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What do you normally use with a partially-filled array?
Antworten
  • An accompanying integer value that holds the number of items stored in the array
  • An accumulator

Frage 41

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To return an array of long values from a method, use this as the return type for the method.
Antworten
  • long[ARRAY_SIZE]
  • long[]

Frage 42

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In order to do a binary search on an array:
Antworten
  • the array must first be sorted in ascending order
  • there are no requirements

Frage 43

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What is the value of scores[2][3] in the following array? int [] [] scores = { {88, 80, 79, 92}, {75, 84, 93, 80}, {98, 95, 92, 94}, {91, 84, 88, 96} };
Antworten
  • 93
  • 94

Frage 44

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The part of a method that is a collection of statements that are performed when the method is executed is called
Antworten
  • argument
  • method body

Frage 45

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An array has a/an __________ size
Antworten
  • fixed
  • dynamic
  • both answers are acceptable

Frage 46

Frage
An ArrayList has a fixed or dynamic size
Antworten
  • False
  • True (either or statement is true)

Frage 47

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When trying to access an element of an array, Java performs array _____ checking to make sure the subscript of the element exists
Antworten
  • method
  • bound

Frage 48

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Given an array variable with the name kiwi, what is the code to get the amount of elements in kiwi?
Antworten
  • kiwi.length
  • kiwi.length;

Frage 49

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Given an ArrayList variable with the name kiwi, what is the code to get the amount of elements in kiwi?
Antworten
  • kiwi.size;
  • kiwi.size()

Frage 50

Frage
Given a String variable with the name kiwi, what is the code to get the amount of characters in kiwi?
Antworten
  • kiwi.length();
  • kiwi.size();

Frage 51

Frage
Classes have _______ which store data
Antworten
  • objects
  • fields

Frage 52

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What is the term used for the character that separates tokens?
Antworten
  • tokenizer
  • delimiter

Frage 53

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What will be the value of x after the following code is executed? int x, y = 2, z = 3; x = (++y)*(++z);
Antworten
  • error, x is undefined
  • 12 (since ++y becomes 3 and ++z becomes 4)

Frage 54

Frage
How many times will the following do-while loop be executed? int x = 5; do { x*=2;} while (x > 10)
Antworten
  • 10
  • 1

Frage 55

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What will be the value of x after the following code is executed? If the code has any kind of syntax error, please type in the answer "error". int x = 1; while (x++ < 10) { x++; }
Antworten
  • 9
  • 12

Frage 56

Frage
How many times will the following for loop be executed? for (int count = 1; count <= 7; count += 3) {System.out.println("Java is great!!!");}
Antworten
  • two
  • three

Frage 57

Frage
What will the following code output to the console? int [ ] integers = new int [5]; System.out.println(integers[0]);
Antworten
  • zero since this is the default value for int
  • one

Frage 58

Frage
What will the following code output to the console? ArrayList<Integer> integers = new ArrayList<>(5); System.out.println(integers.get(0));
Antworten
  • 0
  • error since new array list is not defined

Frage 59

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What is the output? ArrayList<Integer> integers = new ArrayList<>(); integers.add(5); integers.add(7); integers.add(1,18); integers.remove(0); System.out.println(integers.get(0));
Antworten
  • 1
  • 18

Frage 60

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What's the output? ArrayList<String> strings = new ArrayList<>(); strings.add("hi"); strings.add("bye"); strings.add("howdy"); strings.remove(0); System.out.println(strings.get(2));
Antworten
  • howdy
  • error

Frage 61

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What is the output? int[ ] integers = {1,2,3,4,5}; for (int i = 0; i< integers.length; i++) { integers [i]++; } System.out.println(integers[3]);
Antworten
  • five
  • four

Frage 62

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What is the output? int[]integers = new int[10]; final int AMOUNT_OF_RUNS = 20; final int ADD_ME = 5; for (int i = 0; i < AMOUNT_OF_RUNS; i++) { integers[i] += ADD_ME; } System.out.println(integers[3]);
Antworten
  • error because it is asking to run an amount of 20 times when an array is only 10 long
  • 10

Frage 63

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What is the output? int [ ] integers = new int [10]; final int ADD_ME = 5; for (int i = 0; i< integers.length; i++) { integers [i] += ADD_ME*1; } System.out.println(integers[4]);
Antworten
  • error
  • 20

Frage 64

Frage
What is the output? int [ ] [ ] integers = { { 14, 5, 21}, {34, 54}, {3, 6, 7}}; int total = 0; for (int row = 0; row<integers.length; row++) { for (int col = 0; col<integers[0].length; col++) { total += integers[row][col]; } } System.out.println(total);
Antworten
  • Error since this is a ragged array
  • 54

Frage 65

Frage
What is the output? int [ ] [ ] integers = { { 14, 5, 21}, {34, 54}, {3, 6, 7}}; int mysteryVariable = 0; for (int row = 0; row<integers.length; row++) { for (int col = 0; col<integers[row].length; col++) { mysteryVariable++; } } System.out.println(mysteryVariable);
Antworten
  • error
  • 8

Frage 66

Frage
what is the output? int [] [] integers = {{14,5,21{, {34, 54}, {3,6,7}}; int mysteryVariableOne = integers [0][0]; int mysteryVariableTwo = integers [0][0]; for (int row = 0; row < integers.length; row++) { for (int col = 0; col <integes[row].length; col++) { if (mysteryVariableOne < integers[row][col]) { mysteryVariableOne = integers[row][col]; } if (mysteryVariableTwo> integers[row][col]) { mysterVariableTwo = integers[row][col]; }}} System.out.println(myseryVariableOne - mysteryVariableTwo);
Antworten
  • 51 (since 54 is the highest, and 3 is the lowest then 54 - 3 = 51)
  • error

Frage 67

Frage
Output? static ArrayList<String> listOfStrings; public static void main (String[ ] args) { String [ ] strings = {"D", "Z", "G", "P", "M" }; for (String s : strings) listOfStrings.add(s); System.out.println(listOfStrings.get(2)); }
Antworten
  • error
  • G

Frage 68

Frage
Output? static ArrayList<String> listOfStrings; public static void main (String[ ] args) { String [ ] strings = {"D", "Z", "G", "P", "M" }; ArrayList<String> listOfStrings = new ArrayList<>(); for (int i = strings.length-1; i>0; i--) { listOfStrings.add(strings[i] + strings[i-1]); System.out.println(listOfStrings.get(2));
Antworten
  • Error
  • GZ
  • ZD
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