INDIVIDUAL WORK
QUESTION #1 (SELF-CHECK)
Fill in the
blanks.
a) The first element in an array has
index number __________.
b) The last element in an array
containing 35 elements has index number __________.
c) An array of length 12 will have
elements with indexes ranging from _________ to _________.
d) True or false? If attempting to access the element with
index 20 in an array of length 20, you will get an out of bounds
error. __________
e) The __________ of an array or the
____________ of an array refers to the number of elements in the array.
f) True or false? An array in Java can be resized. __________
g) True or false? An array in Java can be given a size at
run-time. __________
h) For an array called data, we can check the number of
elements in it by using __________.
i) The line int x; declares an integer variable named x.
What line of the code declares an integer array name numbers? _______________
j) If grades is a double array, then we can get a String
representation for that array by using ______________.
SOLUTION
Check your
answers here.
QUESTION #2 (SELF-CHECK)
Try doing as many of these quick programs as you can.
A)
Use a one-line statement to create an array
named primes that gets all prime
numbers under 20. Then, again using
a single line, output the array to screen.
B) Create an integer array of length
5. Name your array faves. Use five assignment
statements to store your five favourite numbers into the array. Finally, output the content of your array
to screen.
C) Create a boolean array named flags of size 40. Use a for loop to
set all even elements to true and all odd elements to false. Then output
the contents of the array to screen.
D) Create an int[] of size 20. Use a for loop to initialize each element j to the value j * 2. Output the array to screen.
E) Create an integer array of size
10. Elements 0 and 1 both get a
value of 1. All other elements get
the sum of the two previous elements in the array.
For example, element 2 will get 2 because 1 + 1 is 2.
Your
code should make use of a for loop.
You should output your array to screen.
F) Consider the following statement
that creates an array:
double[] results = {9.6,
9.5, 9.9, 10.0, 9.4};
Write the for loop required to output the value of each element one at a
time on the screen.
SOLUTION
Check your
answers here.
QUESTION #3
In this program, you must ask the user for the
amount of data that will be stored in an array. So, the size of the array is determined
at run-time.
Create a
program that asks the user how many vegetables they like. Then, create a String array named veggies
that will store that number of vegetables.
Then, use a for loop to ask the user to enter the name of each
vegetable they like and store it in the array. Output the content of the array to
screen.
PSEUDOCODE
Ask
the user for the number of veggies they like.
Store
answer in variable named vegCount.
Create
a String array of size vegCount.
Loop
over each element in the array.
Ask user for a veggie they like.
Store result in array
Output
array to screen
SAMPLE OUTPUT
How
many veggies do you like?
3
Enter
a veggie that you like.
Carrot
Enter
a veggie that you like.
Celery
Enter
a veggie that you like.
Cucumber
[Carrot,
Celery, Cucumber]
QUESTION #4
Consider
the five following arrays:
String[] names = {"Rachel", "Joe", "Moni", "Ross", "Chandler", "Phoebe"};
int[] c1 = {78, 62,
85, 94, 82, 90};
int[] c2 = {82, 67,
84, 90, 74, 52};
int[] c3 = {79, 64,
86, 98, 83, 94};
int[] c4 = {92, 82, 85, 74, 80, 62};
The first
array contains student names. The
array c1 contains student marks in course #1. The array c2 contains student marks in
course #2. And so on… The marks have been ordered in the same
way as the student names. So,
Rachel’s marks are 78, 82, 79 and 92 and Chandler’s marks are 82, 74, 83
and 80.
Write the code required to output the name of each
student along with their average.
Your code should also meet the following criteria:
- It should work for
any number of students. So if
we add another student or we drop a student, your code should still
work. This requires you to use
a for loop. You can assume that
all five arrays will always be the same length.
SAMPLE OUTPUT
Rachel
(82.75)
Joe
(68.75)
Moni
(85.0)
Ross
(89.0)
Chandler
(79.75)
Phoebe (74.5)
POSSIBLE ADDITION
If you have
time, can you alter the code to allow for students that have a spare
period. In such a case, the mark
entered in the array would be -1. Of
course, the average has to only consider the other three classes.
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