What does the new operator do?
> Write nested loops to draw this pattern:
> Write a statement that converts the contents of the char variable big to lowercase. The converted value should be assigned to the variable little.
> Assume that the following enumerated data type has been declared: enum Letters { Z, Y, X } What will the following code display? if (Letters.Z.compareTo(Letters.X) > 0) System.out.println("Z is greater than X."); else System.out.println("Z is not greater
> Assume that the following enumerated data type has been declared: enum Creatures{ HOBBIT, ELF, DRAGON } What will the following code display? System.out.println(Creatures.HOBBIT + " " + Creatures.ELF + " " + Creatures.DRAGON);
> Look at the following statement, which declares an enumerated data type: enum Flower { ROSE, DAISY, PETUNIA } 1. What is the name of the data type? 2. What is the ordinal value for the enum constant ROSE? For DAISY? For PETUNIA? 3. What is the fully qual
> Look at the following code. Stock stock1 = new Stock("XYZ", 9.65); Stock stock2 = new Stock("SUNW", 7.92); While the equals method is executing as a result of the following statement, what object does this reference? if (stock2.equals(stock1)) System.out
> Describe the limitation of static methods.
> What action is possible with a static method that isn’t possible with an instance method?
> What is the difference between an instance field and a static field?
> Look at the following statements: int[] numbers1 = { 1, 3, 6, 9 }; int[] numbers2 = { 2, 4, 6, 8 }; int result; Write a statement that multiplies element 0 of the numbers1 array by element 3 of the numbers2 array and assigns the result to the result vari
> Write a statement that creates and initializes a double array with the following Âvalues: 1.7, 6.4, 8.9, 3.1, and 9.2. How many elements are in the array?
> Write an input validation loop that asks the user to enter a number in the range of 1 through 4.
> Show how the double variables temp, weight, and age can be declared in one statement.
> What is the output of the following code? int[] values = new int[5]; for (int count = 0; count < 5; count++) values[count] = count + 1; for (int count = 0; count < 5; count++) System.out.println(values[count]);
> What happens in Java when a program tries to use a subscript that is out-of-bounds?
> What does it mean for a subscript to be out-of-bounds?
> What is the difference between an array’s size declarator and a subscript?
> What is the difference between an ArrayList object’s size and its capacity?
> How do you determine an ArrayList object’s size?
> What would the valid subscript values be in a four-element array of doubles?
> How do you insert an item at a specific location in an ArrayList object?
> How do you retrieve a specific item from an ArrayList object?
> How do you remove an item from an ArrayList object?
> Modify the code you wrote in Question 18 so it adds all of the numbers read from the file and displays their total.
> How do you add items to an ArrayList object?
> Write a statement that creates an ArrayList object and assigns its address to a variable named lizards. The ArrayList should be able to store String objects only.
> Write a statement that creates an ArrayList object and assigns its address to a variable named frogs.
> What import statement must you include in your code in order to use the ArrayList class?
> If a sequential search is performed on an array, and it is known that some items are searched for more frequently than others, how can the contents of the array be reordered to improve the average performance of the search?
> On average, with an array of 20,000 elements, how many comparisons will the sequential search perform?
> Describe the difference between the sequential search and the binary search.
> What’s wrong with the following array declarations? int[ ] readings = new int[−1]; double[ ] measurements = new double[4.5];
> How many times will the selection sort swap the smallest value in an array with another value?
> What value in an array does the selection sort algorithm look for first? When the selection sort finds this value, what does it do with it?
> Write a while loop that lets the user enter a number. The number should be multiplied by 10, and the result stored in the variable product. The loop should iterate as long as product contains a value less than 100.
> A video rental store keeps videos on 50 racks with 10 shelves each. Each shelf holds 25 videos. Declare a three-dimensional array large enough to represent the store’s storage system.
> Recall that we discussed a Rectangle class in Chapter6 . Write code that declares a Rectangle array with five elements. Instantiate each element with a Rectangle object. Use the Rectangle constructor to initialize each object with values for the length a
> 1. Write a statement that declares a String array initialized with the following strings: “Mercuryâ€, “Venusâ€, “Earthâ€, and “Marsâ€. 2. Write a loop that displays the contents of each element in the array you declared in A. 3. Write a loop that
> Write a method named zero, which accepts an int array as an argument and stores the value 0 in each element.
> Look at the following method header: public static void myMethod(double[] array) Here is an array declaration: double[] numbers = new double[100]; Write a statement that passes the numbers array to the myMethod method.
> Look at the following statements: int[] a = { 1, 2, 3, 4, 5, 6, 7 }; int[] b = new int[7]; Write code that copies the a array to the b array.
> A program has the following declaration: double[] values; Write code that asks the user for the size of the array and then creates an array of the specified size, referenced by the values variable.
> A program uses a variable named array that references an array of integers. You do not know the number of elements in the array. Write a for loop that stores −1 in each element of the array.
> Write statements that create the following arrays: 1. A 100-element int array referenced by the variable employeeNumbers. 2. A 25-element double array referenced by the variable payRates. 3. A 14-element float array referenced by the variable miles. 4. A
> In this chapter we used the metaphor of a kite attached to a spool of string to describe the relationship between an object and a reference variable. In this metaphor, does the kite represent an object, or a reference variable?
> Write an if-else statement that displays the String objects title1 and title2 in alphabetical order.
> You hear someone make the following comment: “A blueprint is a design for a house. A carpenter can use the blueprint to build the house. If the carpenter wishes, he or she can build several identical houses from the same blueprint.†Think of this as a
> How is the relationship between an object and a reference variable similar to a kite and a spool of string?
> What values do reference variables hold?
> You have programs that create Scanner, Random, and PrintWriter objects. Where are the Scanner, Random, and PrintWriter classes?
> Will all of a class’s actions always be directly mentioned in the problem domain description?
> How is a class like a blueprint?
> What two questions should you ask to determine a class’s responsibilities?
> What are a class’s responsibilities?
> How do you identify the potential classes in a problem domain description?
> Write an if statement that prints the message “The number is valid†if the variable temperature is within the range −50 through 150.
> When designing an object-oriented application, who should write a description of the problem domain?
> What is a problem domain?
> How many default constructors may a class have?
> Look at the following class: public class CheckPoint { public void message(int x) { System.out.print("This is the first version "); System.out.println("of the method."); } public void message(String x) { System.out.print("This is the second version "); S
> What is a method’s signature?
> Is it required that overloaded methods have different return values, different parameter lists, or both?
> Assume that the following is a constructor, which appears in a class: ClassAct(int number) { item = number; } 1. What is the name of the class that this constructor appears in? 2. Write a statement that creates an object from the class and passes the val
> What are an object’s methods?
> What is a constructor’s return type?
> How is a constructor named?
> A program has a float variable named total and a double variable named number. Write a statement that assigns number to total without causing an error when compiled. Answer: total = (float)number;
> Assume that r1 and r2 are variables that reference Rectangle objects, and the following statements are executed: r1.setLength(5.0); r2.setLength(10.0); r1.setWidth(20.0); r2.setWidth(15.0); Fill in the boxes in Figure6-21 that represent each object&Atild
> What is a stale data item?
> What is an accessor? What is a mutator?
> What does the key word new do?
> Assume that limo is a variable that references an instance of the class shown in ÂFigure6-17 . Write a statement that calls setMake and passes the argument "Cadillac".
> Look at the UML diagram in Figure6-17 and answer the following questions: 1. What is the name of the class? 2. What are the fields? 3. What are the methods? 4. What are the private members? 5. What are the public members?
> A string literal, such as "Joe", causes what type of object to be created?
> When a variable is said to reference an object, what is actually stored in the variable?
> What does an object use its fields for?
> In Java, method arguments are passed by value. What does this mean?
> Assume the double variable number contains the value 12345.6789. Write a statement that uses System.out.printf to display the number as 12,345.68.
> Suppose a method named showValues accepts two int arguments. Which of the following method headers is written correctly? 1. public static void showValues() 2. public static void showValues(int num1, num2) 3. public static void showValues(num1, num2) 4. p
> Look at the following method header: public static void myMethod(int num) Which of the following calls to the method will cause a compiler error? 1. myMethod(7); 2. myMethod(6.2); 3. long x = 99; myMethod(x); 4. short s = 2; myMethod(s);
> What is the difference between an argument and a parameter?
> Write a void method that displays your full name. The method should be named myName.
> What message will the following program display if the user enters 5? What if the user enters 10? What if the user enters 100? import javax.swing.JOptionPane; public class Checkpoint { public static void main(String[] args) { String input; int number; in
> Is the following line of code a method header or a method call? public static void calcTotal()
> Is the following line of code a method header or a method call? calcTotal();
> Write the header for a method named lightYears. The method should return a long and have one long parameter variable: miles.
> Write the header for a method named distance. The method should return a double and have two double parameter variables: rate and time.
> Write the header for a method named days. The method should return an int and have three int parameter variables: years, months, and weeks.
> Write the code to set up all the necessary objects for reading keyboard input. Then write code that asks the user to enter his or her desired annual income. Store the input in a double variable.
> Look at the following method header. What type of value does the method return? public static double getValue(int a, float b, String c)
> What will the following program display? public class Checkpoint { public static void main(String[] args) { int num1 = 99; double num2 = 1.5; System.out.println(num1 + " " + num2); myMethod(num1, num2); System.out.println(num1 + " " + num2); } public sta
> What is the difference between a void method and a value-returning method?
> What will the following program segments display? 1. for (int count = 0; count < 6; count++) System.out.println(count + count); 2. for (int value = −5; value < 5; value++) System.out.println(value); 3. int x; for (x = 5; x
> You want to write a for loop that displays “I love to program†50 times. Assume that you will use a control variable named count. 1. What initialization expression will you use? 2. What test expression will you use? 3. What update expression will you
> Name the three expressions that appear inside the parentheses in the for loop’s header.
> Write an input validation loop that asks the user to enter “Yes†or “Noâ€.
> Write an input validation loop that asks the user to enter ‘Y’, ‘y’, ‘N’, or ‘n’.
> Write an input validation loop that asks the user to enter a number in the range of 10 through 24.
> How many times will "I love Java programming!" be printed in the following program segment? int count = 0; while (count < 10) System.out.println("I love Java programming!);
> Match the conditional expression with the if-else statement that performs the same operation. 1. q = x < y ? a + b : x * 2 ; 2. q = x < y ? x * 2 : a + b; 3. q = x < y ? 0 : 1; if (x < y)  q = 0; else  q = 1; if (x < y)  q = a + b; else  q = x *
