Assignment 1 Basic Java syntax

Assignment 1

Objective
This assignment should help you gain practice with basic Java syntax using
procedural programming, functions, arrays, and console I/O.
Task
Do the following three exercises each in a different file. Your filenames should
be
• Pi.java
• Reverse.java
• DiceStats.java
Each file should have a comment including your name at the top of
the file. Each file should also have appropriate comments throughout
the program.
To do the console input for these exercises, use the java.util.Scanner
class. For random numbers in the last exercise, you may use the java.util.Random
class.
Declare any methods you write to be public and static. You may also
use the java.lang.Math class if you need it. You may assume correct user
input in these problems.
Exercise 1
Filename: Pi.java
Calculate the value of π from the infinite series:
π = 4 − 4/3 + 4/5 − 4/7 + 4/9 − 4/11 + . . .
Print a table that shows the value of π approximated by computing one term
of the series, approximated by two terms, three terms, and so on. Use default
precision for output (do not set any decimal precision).
Start by asking the user how many terms to compute to and then let the
user enter the information. Use this to print a table of the first N terms of the
series (where N is the data entered by the user). Assume the user’s input will be
a non-negative integer. Try to match my sample output as closely as you can.
Be aware that the default precision of System.out.print is different from
that of System.out.printf, so if your precision does not match my output
exactly, it is okay as long as you are using the default for whichever printing
function you are using (I used System.out.printf).
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Sample Run
(Sample user input is underlined)
Compute to how many terms of the series? 20
terms PI approximation
1 4.000000
2 2.666667
3 3.466667
4 2.895238
5 3.339683
6 2.976046
7 3.283738
8 3.017072
9 3.252366
10 3.041840
11 3.232316
12 3.058403
13 3.218403
14 3.070255
15 3.208186
16 3.079153
17 3.200366
18 3.086080
19 3.194188
20 3.091624
Exercise 2
Filename: Reverse.java
Write a static method called reverseDigits that takes a long integer
value and returns that number with its digits reversed. For example, given the
value 1459, the method should return the value 9541 as a long integer.
Write a main() method that enters a loop in which the user is prompted and
allowed to enter any long integer (0 to exit the loop) and the reverseDigits
method is used to compute and return the reversed number. Print this from
the main routine.
You may assume the user inputs a positive integer. Try to match the sample
run exactly.
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Sample Run
(Sample user input is underlined)
Please enter a long integer (0 to quit): 123456
The number reversed is: 654321
Please enter a long integer (0 to quit): 4837946852
The number reversed is: 2586497384
Please enter a long integer (0 to quit): 2345678
The number reversed is: 8765432
Please enter a long integer (0 to quit): 123456789012345678
The number reversed is: 876543210987654321
Please enter a long integer (0 to quit): 234005700
The number reversed is: 7500432
Please enter a long integer (0 to quit): 0
Goodbye!
Exercise 3
Filename: DiceStats.java
Write a program that does the following:
1. Ask the user to enter how many dice will constitute a roll (Some games
require different numbers of dice per turn. Yahtzee takes 5, Monopoly
takes 2, etc.).
2. Ask the user to enter how many rolls they would like to simulate.
3. Create and use an array to keep track of how many times each possible
dice sum appears. Basically, it is a bunch of counters and how many you
need depends on how many dice are rolled per ”turn.”
• Hint: The idea is that this array is a frequency array like the example
we went over in class (number 7.7 from the array lecture)
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• Hint: You determine how many counters you will need based on the
number of dice rolled per turn. The lowest possible total is all 1s, so
the number of dice rolled. The highest possible total is all 6s, so it
is (6 * number of dice). Use this to determine the size of your array.
4. Use a loop to roll the specified number of dice the desired number of
times (and calculate the sum of each roll). Use the array to keep track
the number of times each possible sum appears.
5. Display the results in a table with 3 columns:
(a) the die total
(b) the number of times that total appeared
(c) the percentage of the total rolls that this sum appeared (print the
percentage to 2 decimal places)
Try to match the sample runs as closely as possible. Since randomness
is involved, the number of times each sum appears (and the matching
percentages) will be different, but if you use the same number of dice they
should be similar to the sample run values (if you roll 2 dice at a time,
you should not get a sum of 12 8% of the time, for example). If you
get unexpected values, you may want to try to run it a few more times to
make sure you did not just get unlucky (as any distribution is theoretically
possible).
Sample Run 1
(user input is underlined)
How many dice will constitute one roll? 2
How many rolls? 100000
Sum # of times Percentage
2 2741 2.74 %
3 5540 5.54 %
4 8404 8.40 %
5 11228 11.23 %
6 13835 13.84 %
7 16662 16.66 %
8 13827 13.83 %
9 10989 10.99 %
10 8538 8.54 %
11 5480 5.48 %
12 2756 2.76 %
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Sample Run 2
(user input is underlined)
How many dice will constitute one roll? 4
How many rolls? 100000
Sum # of times Percentage
4 66 0.07 %
5 312 0.31 %
6 773 0.77 %
7 1512 1.51 %
8 2633 2.63 %
9 4313 4.31 %
10 6312 6.31 %
11 8096 8.10 %
12 9660 9.66 %
13 10831 10.83 %
14 11179 11.18 %
15 10720 10.72 %
16 9654 9.65 %
17 7938 7.94 %
18 6158 6.16 %
19 4406 4.41 %
20 2658 2.66 %
21 1613 1.61 %
22 781 0.78 %
23 304 0.30 %
24 81 0.08 %
Compiling
Remember that the compile command is javac at the unix command prompt.
Compile your code on linprog.cs.fsu.edu and run your program with the
java command.
Preparing for Submission
Pack your files into a single jar-file called hw1.jar with the jar utility. To
do this on linprog.cs.fsu.edu (or another terminal environment) use the
following command:
jar cvf hw1.jar Pi.java Reverse.java DiceStats.java
Submitting
I have created a Blackboard submission link for the assignment. It is in the
”Assignments” section of the Blackboard course site. Submit your hw1.jar
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file there.
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