CISC 3115 — Lab #00

Lab 0.1 (Lab 6.6 in the 1115 labs) — Fun with Numbers (InfoOf3) (Approval)

Write a program that reads three numbers from the keyboard, and then prints out some information about the relationships between the numbers-- whether they are all equal, in ascending order, in descending order, and so on. To determine these relationships, you must use the following boolean-valued methods:

boolean allAreEqual(int a, int b, int c);
boolean twoAreEqual(int a, int b, int c); // false if all three are equal
boolean noneAreEqual(int a, int b, int c);
boolean areAscending(int a, int b, int c); // true if a <= b <= c
boolean areDescending(int a, int b, int c); // true if a >= b >= c
boolean strictlyAscending(int a, int b, int c); // true if a < b < c
boolean strictlyDescending(int a, int b, int c); // true if a > b > c

Try to "talk boolean" — i.e., use boolean variables and conditional operators rather than if statements where possible

For example, write:

boolean isNegative = x < 0;

rather than:

boolean isNegative;
if (x < 0)
	isNegtive = true;
else
	isNegative = false;

Sample Test Run

first number? 1
second number? 2
third number? 3
allAreEqual: false
twoAreEqual: false
noneAreEqual: true
areAscending: true
areDescending: false
strictlyAscending: true
strictlyDescending: false

Simple file I/O
Conditionals and logical operators
Simple methods

Lab 0.2 (Lab 9.5 in the 1115 labs) — Calculating Averages (Averages) (Approval)

The file numbers.text consists of sequences of numbers, each sequence preceded by a header value nd then followed by that many integers. Read in the sequences and print their averages. When all sequences have been read in, print out the number of sequences processed. You should not rely on the numbers in each sequence all being on the same line; i.e., do not use nextLine for your input>. You should also not be using an array.

Sample Test Run

For example if the file numbers.text contains:

3 1 2 3
5 12 14 6 
	4 0
10 1 2 3 4 5 
    6 7 8 9 10
1 17
2 90 80

the program should produce the following output:

The average of the 3 integers 1 2 3 is 2.0
The average of the 5 integers 12 14 6 4 0 is 7.2
The average of the 10 integers 1 2 3 4 5 6 7 8 9 10 is 5.5
The average of the 1 integers 17 is 17.0
The average of the 2 integers 90 80 is 85.0
5 sets of numbers processed

This data in this example is of a somewhat more complex structure — both eof and header value processing is required (the former to determine when there are no more sequences, and the latter to process each sequence).

Lab 0.3 (Lab 10.4 in the 1115 labs) — Finding the Last Occurrence of a Value in a File (FindLast) (Approval)

Write a program that prompts the user (at the keyboard)for a value and searches the file numbers.text for that value, printing out the last position where the number appears in the file (the first number in the file is at position 1). If the number does not appear in the file, print out an appropriate message. Continue asking the user for values until they signal end-of-file (i.e., in Windows one enters end-of-file at the keyboard by entering Ctl-Z, in Unix end-of-file is indicated by entering Ctl-D). The logic is the same as end-of-file for a disk file-- i.e., if your Scanner variable is named 'keyboard', you would have the loop condition 'while (keyboard.hasNextInt())'.

You may not use an array or any other data structure.

Sample Test Run

For example if the file numbers.text contains:

execution of the program should look like:

Enter a number: 10
10 last appears in the file at position 9
Enter a number: 29
29 does not appear in the file
Enter a number: 9
9 last appears in the file at position 12
Enter a number:

Some Guidance and Notes

Write a method int findLast(int val), that accepts the value to be searched, creates a Scanner object for the file numbers.text and searches the file
- The search logic is a bit different since we're interested in the last occurrence, not the first.
  - With an array (coming soon), we could search backwards; however, there's no way for us to do that with a file (at least not with a Scanner).
In your main method, have a Scanner for the keyboard, prompt the user for values, call the above method with the value read in, and use the returned value to determine what to print.
Refer to Lecture 9 for handling eof at the keyboard.

A variation of a forward search through the file.
Practice with two scanners and eof processing from the keyboard
Somewhat involved logic — keeping track of most recent position of searched value

Lab 0.4 (Lab 12.1 in the 1115 labs) — Array Information (ArrayInfo) (Approval)

The file numbers.text contains a header value, followed by that many double values. Create an array of the appropriate size, populate the array with the doubles, and print out various information about the array (see below).

Sample Test Run

For example if the file numbers.text contains:

the program should produce the following output:

The array: {12.3, 2.5, 9.4, 3.14, 22.15, 17.0, 54.3, 7.6} contains 8 elements
The first element of the array is 12.3
The last element of the array is 7.6 and is at position 7
The middle element of the array is 3.14 and is at position 3
The largest element of the array is 54.3 and is at position 6
The smallest element of the array is 2.5 and is at position 1

Notes:

You should be using methods for printing, and the max/min calculations.
Notice the array is printed using comma logic.
- Even though I'm not holding you responsible for remembering the logic for reproduction on an exam, there's no reason you shouldn't use it in an assignment, where you have access to the proper code in the lecture notes.
Feel free to copy any of the code/methods from lecture 12 (there's no real need to use the first, last, or middle methods — — feel free to simply use the proper subscripts).
While the max method presented inthe lecture notes is useful, it is not enough; you are not just being asked to print out the largest and smallest value, you are also required to print out their positions (i.e., indexes in the array). You thus should consider writing a maxPos method that returns the index (rather than the actual value) of the largest element in the array (same for minimu).

Reading in data using a header value
More practice with arrays
'Muscle-memory practice for comma logic
A variation on the max method; this also emphasizes the distinction between the value of the element and its index (position/location within the array).

Lab 0.5 (Lab 15.1 in the 1115 labs) — Sorting Parallel Arrays Information (ParellelArraysSort) (Approval)

Given the file roster.text, containing pairs of ids (integers) and gpa's (doubles), read the file into a pair of arrays, and perform two sorts on them, the first by name in ascending order, the second by gpa in descending order. Print out the original and sorted arrays.

You can use the sort of your choice (bubble or selection, or one for each sort :) )
Assume no more than 100 entries

Suggested Methods

While you are free to code this lab as you wish, I would recommend the following methods:

The usual read method … accepts either the filename or a Scanner object created by main, together with the arrays and the capacity. The method loads up the arrays returns the number of entries read in.

Two sort methods, both accepting the two arrays and numbers of entries in the arrays (size). Since the two methods have the exact same signature, they cannot be overload (i.e., use the exact same name) … I used the named sortById and sortByGPA

swap accepts an array and a pair of indexes and swaps the values at those two indices (look at Lecture 12 for details on swapping elements of an array). You need two of these methods, one for swapping the elements of the id (int) array and the other for the gpa (double) array. Since these two methods will have different signatures (i.e., their paraeter lists are not identcal), you can use the same name for both (I used swap).

print accepting bot arrays and the size and prints them out in the appropriate manner

Other Suggestions

If you don't already know how to copy/paste, learn how to do it and try using it. There are numerous opportunities here:
- copy my swap code from Lecture 12
- copy one of my read methods from the notes or the solutions to the sample finals
- you have two sets of methods that are in pairs: sortBy and swap. Write one and copy to the other.
A word of caution, make sure you also understand the code you are copying; it's often too easy t copy without understanding the code, and that sort of defeats the purpose of doing these exercises.

Sample Test Run

For example if the file roster.text contains:

the program should produce the following output:

Original data:
10050: 3.1
10721: 2.3
10010: 3.7
30921: 2.5
23462: 4.0
12345: 2.9

Sorted by Id:
10010: 3.7
10050: 3.1
10721: 2.3
12345: 2.9
23462: 4.0
30921: 2.5

Reverse Sorted by GPA:
23462: 4.0
10010: 3.7
10050: 3.1
12345: 2.9
30921: 2.5
10721: 2.3

CISC 1115
Introduction to Modern Programming Techniques
Lab #00
Review

How to Develop and Submit your Labs

Lab 0.1 (Lab 6.6 in the 1115 labs) — Fun with Numbers (InfoOf3) (Approval)

Lab 0.2 (Lab 9.5 in the 1115 labs) — Calculating Averages (Averages) (Approval)

Lab 0.3 (Lab 10.4 in the 1115 labs) — Finding the Last Occurrence of a Value in a File (FindLast) (Approval)

Some Guidance and Notes

Lab 0.4 (Lab 12.1 in the 1115 labs) — Array Information (ArrayInfo) (Approval)

Lab 0.5 (Lab 15.1 in the 1115 labs) — Sorting Parallel Arrays Information (ParellelArraysSort) (Approval)

Suggested Methods

Other Suggestions

CISC 1115 Introduction to Modern Programming Techniques Lab #00 Review

How to Develop and Submit your Labs

Lab 0.1 (Lab 6.6 in the 1115 labs) — Fun with Numbers (InfoOf3) (Approval)

Lab 0.2 (Lab 9.5 in the 1115 labs) — Calculating Averages (Averages) (Approval)

Lab 0.3 (Lab 10.4 in the 1115 labs) — Finding the Last Occurrence of a Value in a File (FindLast) (Approval)

Some Guidance and Notes

Lab 0.4 (Lab 12.1 in the 1115 labs) — Array Information (ArrayInfo) (Approval)

Lab 0.5 (Lab 15.1 in the 1115 labs) — Sorting Parallel Arrays Information (ParellelArraysSort) (Approval)

Suggested Methods

Other Suggestions

CISC 1115
Introduction to Modern Programming Techniques
Lab #00
Review