Code Line
stringclasses 57
values | User Explanation
stringclasses 692
values | Line-Explanation in PCEX
stringclasses 131
values | Annotation Score
float64 1
5
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} while (num > 0);
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Break once we've removed all the digits in the number
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We need to check for termination conditions to avoid infinite loops.
| 1 |
} while (num > 0);
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Break once we've removed all the digits in the number
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The loop should terminate when we run out of digits to process.
| 3 |
} while (num > 0);
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Break once we've removed all the digits in the number
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We could check whether the are more digits left by checking whether the variable num, which gets updated in the body of the do loop, is greater than zero.
| 1 |
} while (num > 0);
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Break once we've removed all the digits in the number
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If variable num is greater than zero, then it must have at least one digit, and in that case, the body of the do loop will be repeated again.
| 1 |
} while (num > 0);
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Break once we've removed all the digits in the number
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The body of the while loop should repeat as long as there are more digits left that we have not processed yet.
| 3 |
Scanner scan = new Scanner(System.in);
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Set up a scanner to read in user inputs
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To read the input values from the user, we need to define a Scanner object.
| 4 |
Scanner scan = new Scanner(System.in);
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Set up a scanner to read in user inputs
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We need to read and process the values that the user enters.
| 3 |
System.out.println("Enter the phone age in years:");
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Prompt the user to input the phone age
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We prompt the user to enter the phone age in years.
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int phoneAge = scan.nextInt();
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Read in the user's input as an integer
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We read the phone age by calling the nextInt() method because this input is an integer.
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int phoneAge = scan.nextInt();
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Read in the user's input as an integer
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We need to read the phone age that the user enters and store it in a variable.
| 3 |
System.out.println("Enter whether the phone is broken (true or false):");
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Prompt the user to input whether the phone is broken or not
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We prompt the user to enter whether the phone is broken.
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boolean isBroken = scan.nextBoolean();
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Read in the user's input as to whether the phone is broken
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We need to read whether the phone is broken and store it in a variable.
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boolean isBroken = scan.nextBoolean();
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Read in the user's input as to whether the phone is broken
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The variable isBroken is true when the phone is broken, and false otherwise.
| 1 |
boolean isBroken = scan.nextBoolean();
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Read in the user's input as to whether the phone is broken
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We read whether the phone is broken by calling the nextBoolean() method because this input is a boolean.
| 2 |
scan.close();
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Stop reading in user inputs
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We close the scanner as we do not want to process any input from the user in the rest of the program.
| 2 |
boolean needPhone = isBroken || phoneAge >= 3;
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Find out if the phone is broken or if it is too old using the logical or operator
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We use the || operator (called or) to combine the two conditions.
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boolean needPhone = isBroken || phoneAge >= 3;
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Find out if the phone is broken or if it is too old using the logical or operator
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The first condition is to test if the phone is broken and the second condition is to test if the phone age is at least 3 years old.
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boolean needPhone = isBroken || phoneAge >= 3;
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Find out if the phone is broken or if it is too old using the logical or operator
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We need two conditions to determine if it is the time for a new phone.
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System.out.println(needPhone);
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Tell the user whether they need a new phone or not
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This statement prints true/false depending on whether it is time to buy a new phone.
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System.out.println(needPhone);
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Tell the user whether they need a new phone or not
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The printed value is followed by an end-of-line character in the end.
| 1 |
for (int num = 2; num <= 10; num += 2) {
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Go through all even integers starting at two and ending at ten
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To do this, we need to use a loop structure.
| 1 |
for (int num = 2; num <= 10; num += 2) {
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Go through all even integers starting at two and ending at ten
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We need to repeat the same process for each of the even positive integers that are less than or equal to 10.
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for (int num = 2; num <= 10; num += 2) {
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Go through all even integers starting at two and ending at ten
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To do this, we initialize variable num to 2, loop until reaching 10 (inclusive), and increment num by 2 after each iteration of the loop.
| 3 |
for (int num = 2; num <= 10; num += 2) {
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Go through all even integers starting at two and ending at ten
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We use for loops instead of a while loop because we need to repeat the loop a certain number of times, and for loops are best-suited in cases like this when we know ahead of time the number of times that we need to repeat the loop.
| 1 |
for (int num = 2; num <= 10; num += 2) {
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Go through all even integers starting at two and ending at ten
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Here, we want the for loop to start counting from 2 (2 is the first positive even number) with every even integer number up to (including) 10.
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System.out.println(num + " squared = " + (num * num));
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Print out the square of the current even integer
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The multiplication may also be performed directly in the println statement.
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System.out.println(num + " squared = " + (num * num));
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Print out the square of the current even integer
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Note that we do not necessarily have to store the squared number in a variable.
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System.out.println(num + " squared = " + (num * num));
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Print out the square of the current even integer
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To square each number in the sequence, we multiply it by itself using the multiplication (*) operator.
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System.out.println(num + " squared = " + (num * num));
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Print out the square of the current even integer
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In each iteration of the loop, this statement prints the square number to the default standard output stream.
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Point1 point = new Point1();
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Generate an instance of the Point class
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This statement creates a Point1 object using the new keyword and empty parentheses.
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Point1 point = new Point1();
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Generate an instance of the Point class
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The variable point holds a reference to a Point1 object.
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point.setX(7);
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Set the x value in this point class
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This statement invokes the method setX of the point to set its x-coordinate to 7.
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point.translate(11, 6);
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Move the point by 11 in the x direction and 6 in the y direction
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This statement invokes the method translate of the point.
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point.translate(11, 6);
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Move the point by 11 in the x direction and 6 in the y direction
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The second parameter specifies how much we want to shift the y-coordinate of the point.
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point.translate(11, 6);
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Move the point by 11 in the x direction and 6 in the y direction
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The translate method receives two parameters.
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point.translate(11, 6);
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Move the point by 11 in the x direction and 6 in the y direction
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The first parameter specifies how much we want to shift the x-coordinate of the point.
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System.out.println("The point's coordinates: (" + point.getX() + ", " + point.getY() + ")") ;
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Print out the new coordinates of the point after translation by using the getters of the class
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Note that we do not necessarily have to store the returned value from each of these methods in a variable.
| 1 |
System.out.println("The point's coordinates: (" + point.getX() + ", " + point.getY() + ")") ;
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Print out the new coordinates of the point after translation by using the getters of the class
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We could use the returned value of them directly in the println statement.
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System.out.println("The point's coordinates: (" + point.getX() + ", " + point.getY() + ")") ;
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Print out the new coordinates of the point after translation by using the getters of the class
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This statement prints the coordinates of the point to the default standard output stream.
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System.out.println("The point's coordinates: (" + point.getX() + ", " + point.getY() + ")") ;
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Print out the new coordinates of the point after translation by using the getters of the class
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The printed text is followed by the end-of-line character at the end.
| 1 |
System.out.println("The point's coordinates: (" + point.getX() + ", " + point.getY() + ")") ;
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Print out the new coordinates of the point after translation by using the getters of the class
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To get the point's coordinates, we invoke the method getX and getY of the point.
| 3 |
class Point1 {
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Declare a new class called Point1
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We define the class Point1 to represent a point in the Euclidean plane.
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private int y;
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Store the y value of the point
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Therefore, we need to declare an instance variable for the class to store the y-coordinate of the point.
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private int y;
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Store the y value of the point
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We declare it as integer because we want to have integer coordinates for the point.
| 1 |
private int y;
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Store the y value of the point
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Note that an instance variable is a variable defined in a class, for which each instantiated object of the class has a separate copy, or instance.
| 1 |
private int y;
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Store the y value of the point
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Every object of the Point1 class will have its own y-coordinate.
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public void translate(int dx, int dy) {
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Define a method for the class to translate the point by a certain amount in the x and y direction
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This method shifts the coordinates by a specific delta-x and delta-y, which are passed as parameters.
| 3 |
public void translate(int dx, int dy) {
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Define a method for the class to translate the point by a certain amount in the x and y direction
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We define this method as public to provide access to this method from outside of the class.
| 1 |
public void translate(int dx, int dy) {
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Define a method for the class to translate the point by a certain amount in the x and y direction
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Also, we define its return type as void, as it does not return any value.
| 1 |
public void translate(int dx, int dy) {
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Define a method for the class to translate the point by a certain amount in the x and y direction
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Note that both of the parameters are declared as integers because the point has integer coordinates.
| 1 |
x += dx;
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Move the point by the incoming dx value
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To shift the x-coordinate of the point, we need to add dx to the value of the x-coordinate of the point.
| 3 |
x += dx;
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Increment the point by the dx value
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To shift the x-coordinate of the point, we need to add dx to the value of the x-coordinate of the point.
| 3 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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Also, we define its return type as void, as it does not return any value.
| 1 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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We define this method as public to provide access to this method from outside of the class.
| 1 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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This method sets the current value of the x-coordinate of the point to the given value (newX) that is specified as the method's parameter.
| 2 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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Note that the instance variable x is private; thus, it cannot be directly changed from outside the class.
| 1 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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The parameter of the method is declared as integer because the x-coordinate of the point is an integer.
| 1 |
public void setX(int newX) {
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Define a method to set a value for the point's x value
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It can be changed from outside the class only through this method.
| 1 |
public int getX() {
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Define a method to get the current x coordinate of the point
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We define this method as public to provide access to this method from outside of the class.
| 2 |
public int getX() {
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Define a method to get the current x coordinate of the point
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This method returns the x-coordinate of the point.
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public int getX() {
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Define a method to get the current x coordinate of the point
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Note that the instance variable x is private; thus, it cannot be directly accessed from outside the class.
| 2 |
public int getX() {
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Define a method to get the current x coordinate of the point
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Also, we define its return type as int, as it returns the x-coordinate of the point which is an integer.
| 2 |
public int getX() {
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Define a method to get the current x coordinate of the point
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It can be accessed from outside the class only through this getter method.
| 2 |
Scanner scan = new Scanner(System.in);
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creates a new Scanner instance which points to the input stream passed as argument.
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To read the input value from the user, we need to define a Scanner object.
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Scanner scan = new Scanner(System.in);
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creates a new Scanner instance which points to the input stream passed as argument.
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We need to read and process the integer that the user enters.
| 1 |
System.out.println("Enter an integer: ");
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this code line prints the text "Enter an integer: "
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We prompt the user to enter an integer.
| 5 |
int num = scan.nextInt();
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This code line creates the integer called num and gives to it the value of the input number
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We read the input integer by calling the nextInt() method because this input is an integer.
| 3 |
int num = scan.nextInt();
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This code line creates the integer called num and gives to it the value of the input number
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We need to read the integer that the user enters and store it in a variable.
| 3 |
if ( num > 0 ) {
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It's a if cycle, it does what is after the brace if the integer "num" is greater than 0
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If the integer is neither positive nor negative, then we could conclude that the integer is zero.
| 1 |
if ( num > 0 ) {
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It's a if cycle, it does what is after the brace if the integer "num" is greater than 0
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The conditions that tests for the integer's sign are mutually exclusive (i.e., one and only one of the conditions can be true); therefore, their order does not matter.
| 1 |
if ( num > 0 ) {
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It's a if cycle, it does what is after the brace if the integer "num" is greater than 0
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To determine the sign of the integer, we need to perform two tests: one for determining whether the integer is positive and one for determining whether the integer is negative.
| 1 |
if ( num > 0 ) {
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It's a if cycle, it does what is after the brace if the integer "num" is greater than 0
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Also, it is better to use if-else if statements instead of sequential if statements because an integer has only one sign and once we find the sign, we don't need to perform more tests.
| 1 |
if ( num > 0 ) {
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It's a if cycle, it does what is after the brace if the integer "num" is greater than 0
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If both of these tests fail, then we could conclude that the integer is zero.
| 1 |
System.out.println("The integer is positivie.");
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This code line prints the text "The integer is positive."
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This statement prints that the integer is positive.
| 5 |
System.out.println("The integer is positivie.");
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This code line prints the text "The integer is positive."
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The printed text is followed by the end-of-line character at the end.
| 1 |
} else if ( num < 0 ) {
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It's a else if statement. If the the integer "num" is smaller than 0 it does the instructions after the brace.
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If the first test fails (i.e., when the integer is not positive), we need to test if the integer is negative.
| 2 |
System.out.println("The integer is negative.");
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This code line prints the text "The integer is negative."
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The printed text is followed by the end-of-line character at the end.
| 1 |
System.out.println("The integer is negative.");
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This code line prints the text "The integer is negative."
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This statement prints that the integer is negative.
| 5 |
} else {
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It's a else statement. If the integer "num" it's not greater or smaller than 0 (so it's equal to zero) it does the instructions after the brace.
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We need to end the above if-else if statements with an else statement that its body is executed when none of the above tests are true, that is when the integer is zero.
| 2 |
System.out.println("The integer is zero.");
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This code line prints the text "The integer is zero."
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The printed text is followed by the end-of-line character at the end.
| 2 |
System.out.println("The integer is zero.");
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This code line prints the text "The integer is zero."
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This statement prints that the integer is zero.
| 5 |
System.out.println("The integer is zero.");
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This code line prints the text "The integer is zero."
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The printed text is followed by the end-of-line character at the end.
| 1 |
System.out.println("The integer is zero.");
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This code line prints the text "The integer is zero."
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This statement prints that the integer is zero.
| 5 |
scan.close();
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It closes this scanner.
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We close the scanner as we do not want to process any input from the user in the rest of the program.
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int [] arr = { 1, 2, 3};
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It declares an Array of integers.
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We initialize the array of type int to hold the specified numbers.
| 3 |
int [] arr = { 1, 2, 3};
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It declares an Array of integers.
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We initialize the array by separating elements with a comma and enclosing the collection in braces { }.
| 2 |
for ( int i = 0; i < arr.length; i++ ) {
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It's a for cycle.
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We want to iterate over the array and increment each element in the array by 1.
| 1 |
for ( int i = 0; i < arr.length; i++ ) {
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It's a for cycle.
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To really change the array as we march across it, we need to use indexes so we can assign an updated value to each position as we go.
| 1 |
for ( int i = 0; i < arr.length; i++ ) {
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It's a for cycle.
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We need the array indexes to start at 0 (array indexes start from 0) with every integer number up to but not including the array length.
| 1 |
for ( int i = 0; i < arr.length; i++ ) {
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It does the instructions after the brace as long as the integer i is smallar than the length of the array.
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We want to iterate over the array and increment each element in the array by 1.
| 1 |
for ( int i = 0; i < arr.length; i++ ) {
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It does the instructions after the brace as long as the integer i is smallar than the length of the array.
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To really change the array as we march across it, we need to use indexes so we can assign an updated value to each position as we go.
| 1 |
for ( int i = 0; i < arr.length; i++ ) {
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It does the instructions after the brace as long as the integer i is smallar than the length of the array.
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We need the array indexes to start at 0 (array indexes start from 0) with every integer number up to but not including the array length.
| 2 |
for ( int i = 0; i < arr.length; i++ ) {
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After every cycle increment the value of i of 1.
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We want to iterate over the array and increment each element in the array by 1.
| 4 |
for ( int i = 0; i < arr.length; i++ ) {
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After every cycle increment the value of i of 1.
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To really change the array as we march across it, we need to use indexes so we can assign an updated value to each position as we go.
| 2 |
for ( int i = 0; i < arr.length; i++ ) {
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After every cycle increment the value of i of 1.
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We need the array indexes to start at 0 (array indexes start from 0) with every integer number up to but not including the array length.
| 3 |
arr[i] += 1;
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Increment the value of the i-element of the array by 1.
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This statement increments the element at the index i of the array by 1.
| 4 |
Scanner scan = new Scanner(System.in);
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Creating a scanner variable that is used to take input from the user.
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To read the input value from the user, we need to define a Scanner object.
| 3 |
Scanner scan = new Scanner(System.in);
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Creating a scanner variable that is used to take input from the user.
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We need to read and process the value that the user enters.
| 4 |
System.out.println("Enter an integer for seconds: ");
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Printing a prompt asking for user input
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We prompt the user to enter the seconds.
| 5 |
int seconds = scan.nextInt();
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Using the scanner variable created before to take input from user.
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We need to read the seconds that the user enters and store it in a variable.
| 3 |
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