JAVA: test yourself to write Methods ( solutions is available) ~ gwax programs

For each exercise below, write the method described. Give all of the methods public
visibility. Assume all ranges are inclusive (include both end points).

1. Write a method called powersOfTwo that prints the first 10 powers of 2 (starting
with 2). The method takes no parameters and doesn't return anything.

2. Write a method called alarm that prints the word “Alarm!” multiple times on
separate lines. The method should accept an integer parameter that specifies how
many times the output line is printed.

3. Write a method called sum100 that returns the sum of the integers from 1 to 100.
public int sum100 ()

4. Write a method called sumRange that accepts two integer parameters that
represent a range. You may assume the first parameter is less than or equal to the
second. The method should return the sum of the integers in that range.
public int sumRange (int low, int high)

5. Write a method called maxOfTwo that accepts two integer parameters and
returns the larger of the two.

6. Write a method called larger that accepts two floating point parameters (of type
double) and returns true if the first parameter is greater than the second, and
false otherwise.

7. Write a method called countA that accepts a String parameter and returns the
number of times the letter 'A' is found in the string.

8. Write a method called evenlyDivisible that accepts two integer parameters and
returns true if the first parameter is evenly divisible by the second, or vise versa,
and false otherwise. You may assume that neither parameter is zero.

9. Write a method called average that accepts three integer parameters and returns
their average as a floating point value.

10. Overload the average method of the previous exercise such that if four integers
are provided as parameters, the method returns the average of all four.

11. Overload the average method once more to accept five integer parameters and
return their average.

12. Write a method called multiConcat that takes a String and an integer as
parameters, and returns a String that is the parameter string concatenated with
itself n number of times (where n is the second parameter). For example, if the
parameters are "hi" and 4, the return value is "hihihihi".

13. Overload the multiConcat method from the previous example such that if the
integer parameter is not provided, the method returns the string concatenated with
itself. For example, if the parameter is "test" the return value is "testtest".

14. Write a method called isAlpha that accepts a character parameter and returns true
if that character is either an uppercase or lowercase alphabetic letter.

15. Write a method called validate that accepts three integer parameters. The first
two parameters represent a range, and the purpose of the method is to verify that
the value of the third parameter is in that range. You may assume that the first
parameter is less than or equal to the second. If the third parameter is not in the
specified range, the method should prompt the user and read a new value. This
new value should be tested for validity as well. The method should only return to
the calling method once a valid value has been obtained, and it should return the
valid value.

16. Write a method called floatEquals that accepts three floating point values as
parameters. The method should return true if the first two parameters are
essentially equal, within the tolerance of the third parameter.

17. Write a method called reverse that accepts a String as a parameter and returns
a String that contains the characters of the parameter in reverse order. Note:
there is actually a method in the String class that performs this operation, but
for the sake of this exercise you will write your own.

18. Write a method called isIsoceles that accepts three integer parameters that
represent the lengths of the sides of a triangle. The method should return true if
the triangle is isosceles but not equilateral, meaning that exactly two of the sides
have an equal length, and false otherwise.

19. Write a method called randomInRange that accepts two integer parameters
representing a range. You may assume that the first parameter is less than or equal
to the second, and that both are positive. The method should return a random
integer in the specified range.

20. Overload the randomInRange method of the previous exercise such that if only
one parameter is provided, the range is assumed to be from 1 to that value. You
may assume the parameter value is positive.

21. Write a method called randomColor that creates and returns a Color object that
represents a random color. Recall that a Color object can be defined by three
integer values between 0 and 255 representing the contributions of red, green, and
blue (its RGB value).

22. Write a method called darken that accepts a Color object as a parameter and
returns a new Color object that is "darker" than the parameter. Create the darker
color using RGB values that are 10 percent less than the original.

23. Write a method called drawCircle that draws a circle based on the method's
parameters: a Graphics object through which to draw the circle, two integer
values that define the (x, y) coordinate of the center of the circle, another integer
that represents the circle's radius, and a Color object that defines the circle's
color. The method does not return anything.

24. Overload the drawCircle method of the previous exercise such that if the Color
parameter is not provided, the circle's color will default to black.

Exercise Worksheet Java Software Solutions
25. Overload the drawCircle method again such that if the radius is not provided, a
random radius in the range 10 to 100 will be used.

26. Overload the drawCircle method yet again such that if both the color and radius
of the circle are not provided, the color will default to red and the radius will
default to 40.