What would be wrong with not writing a return statement in a value-returning method? Can you have a return statement in a void method? Does the return statement in the following method cause syntax errors?

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

Evaluate the following expressions:

2 * 2 – 3 > 2 && 4 – 2 > 5
2 * 2 – 3 > 2 || 4 – 2 > 5

What is the return type of a main method?

(Sort three numbers) Write a method with the following header to display three numbers in decreasing order:

public static void displaySortedNumbers( double num1, double num2, double num3)

Write a test program that prompts the user to enter three numbers and invokes the method to display them in decreasing order.

Write a method with the following header to display three numbers in increasing order:

public static void displaySortedNumbers(
   double num1, double num2, double num3)

Write a test program that prompts the user to enter three numbers and invokes the method to display them in increasing order.

(Display an integer reversed) Write a method with the following header to ­display an integer in reverse order:

public static void reverse(int number)

For example, reverse(3456) displays 6543 . Write a test program that prompts the user to enter an integer then displays its reversal.

True or false? A call to a method with a void return type is always a statement itself, but a call to a value-returning method cannot be a statement by itself.

One foot equals 12 inches. Write a function named feet_to_inches that accepts a number of feet as an argument and returns the number of inches in that many feet. Use the function in a program that prompts the user to enter a number of feet and then displays the number of inches in that many feet.

(Geometry: point position) Programming Exercise 3.32 shows how to test whether a point is on the left side of a directed line, on the right, or on the same line. Write the methods with the following headers:

/** Return true if point (x2, y2) is on the left side of the
* directed line from (x0, y0) to (x1, y1) */
public static boolean leftOfTheLine(double x0, double y0,
double x1, double y1, double x2, double y2)

/** Return true if point (x2, y2) is on the same
* line from (x0, y0) to (x1, y1) */
public static boolean onTheSameLine(double x0, double y0,
double x1, double y1, double x2, double y2)

/** Return true if point (x2, y2) is on the
* line segment from (x0, y0) to (x1, y1) */
public static boolean onTheLineSegment(double x0, double y0,
double x1, double y1, double x2, double y2)

Write a program that prompts the user to enter the three points for p0 , p1 , and p2 and displays whether p2 is on the left side of the line from p0 to p1 , right side, the same line, or on the line segment. Here are some sample runs:

Enter three points for p0, p1, and p2: 1 1 2 2 1.5 1.5
(1.5, 1.5) is on the line segment from (1.0, 1.0) to (2.0, 2.0)

Enter three points for p0, p1, and p2: 1 1 2 2 3 3
(3.0, 3.0) is on the same line from (1.0, 1.0) to (2.0, 2.0)

Enter three points for p0, p1, and p2: 1 1 2 2 1 1.5
(1.0, 1.5) is on the left side of the line
from (1.0, 1.0) to (2.0, 2.0)

Enter three points for p0, p1, and p2: 1 1 2 2 1 –1
(1.0, −1.0) is on the right side of the line
from (1.0, 1.0) to (2.0, 2.0)

(Geometry: points in triangle?) Suppose a right triangle is placed in a plane as shown below. The right-angle point is placed at $(0, 0)$, and the other two points are placed at $(200, 0)$ and $(0, 100)$. Write a program that prompts the user to enter a point with x- and y-coordinates and determines whether the point is inside the triangle. Here are the sample runs:

Enter a point’s x- and y-coordinates: 100.5 25.5
The point is in the triangle

Use the methods in the following program to print 100 uppercase letters and then 100 single digits, printing ten per line.

1   public class RandomCharacter {
2       /** Generate a random character between ch1 and ch2 */
3       public static char getRandomCharacter(char ch1, char ch2) {
4           return (char)(ch1 + Math.random() * (ch2 - ch1 + 1));
5       }
6
7       /** Generate a random lowercase letter */
8       public static char getRandomLowerCaseLetter() {
9           return getRandomCharacter('a', 'z');
10      }
11
12      /** Generate a random uppercase letter */
13      public static char getRandomUpperCaseLetter() {
14          return getRandomCharacter('A', 'Z');
15      }
16
17      /** Generate a random digit character */
18      public static char getRandomDigitCharacter() {
19          return getRandomCharacter('0', '9');
20      }
21
22      /** Generate a random character */
23      public static char getRandomCharacter() {
24          return getRandomCharacter('\u0000', '\uFFFF');
25      }
26  }

(Geometry: points in triangle?) Suppose a right triangle is placed in a plane. The right-angle point is placed at (0, 0), and the other two points are placed at (200, 0), and (0, 100). Write a program that prompts the user to enter a point with x- and y-coordinates and determines whether the point is inside the triangle.

Suppose a right triangle is placed in a plane as shown below. The right-angle point is placed at (0, 0), and the other two points are placed at (200, 0) and (0, 100). Write a program that prompts the user to enter a point with x- and y-coordinates and determines whether the point is inside the triangle.

Write a method with the following header to format the integer with the specified width. public static String format(int number, int width) The method returns a string for the number with one or more prefix 0s. The size of the string is the width. For example, format(34, 4) returns 0034 and format(34, 5) returns 00034. If the number is longer than the width, the method returns the string representation for the number. For example, format(34, 1) returns 34. Write a test program that prompts the user to enter a number and its width and displays a string returned by invoking format(number, width).