PROJECT Java File Processing Application: Java Data Analytics Objective To type
ID: 3858354 • Letter: P
Question
PROJECT Java File Processing Application: Java Data Analytics
Objective To type a simple Java program, execute ( run ) the program for some particular values, observe the output and then modify the program.
PROJECT DESCRIPTION
Design an application that uses sequential file processing to analyze a list of data values.
The initial starter code for your program is given in Figure 1 .
First run and test the starter code, which primarily has file processing objects that declare a file and write data to the file.
After you test the original starter code and verify its functionality, you will then modify the program according to the instructions that follow.
Your completed program ( after modification ) will perform, at the minimum, each of the following tasks
• read from a text file and write to a text file
• include a method that displays the data array, when requested
• include a method to sort the data in the text file
• locate the maximum and minimum values in the array
• compute the average value of the data values
Basically, your program is outlined in the given starter code statements shown within Figure 1 , which follows. Review the starter code to understand the mechanisms of the interactions between reading a file and writing to a file. Perform any modifications according to this project’s instructions.
Type, compile and run the basic Java program that is shown in Figure 1 , which follows. Then modify the program accordingly.
Information About This Project
The types of file processing include:
sequential access file processing data is accessed one line at a time
random access file processing data can be assessed in any order
Steps to Complete This Project
STEP 1 Open NetBeans or Eclipse
Open NetBeans or Eclipse and create a Java project with the following details.
For Project Name include: DataAnalytics
For the Main Class include: DataAnalytics
In your Code window for this class, shown below, copy the program code shown in Figure 1 below, in the appropriate places, except substitute your own name in place of Sammy Student.
STEP 2 Review the Starter Code for this Project
Before you run the initial starter code for this project, which is given in Figure 1 review the program statements that comprise the code. Basically, the starter code assigns a file name to a file writing object. A looping structure is then used to take values from the user and assign them to an array list. The data is also recorded to the declared text file.
PROJECT Java File Processing Application: Java Data Analytics
Figure 1 Source Code for the Data Analytics File Processing Program
import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;
// Sammy Student: Data Analysis with Java File Processing
class DataAnalytics
{
public static void main(String args[])
{
// declare an object to receive the data
Scanner scan = new Scanner(System.in);
// declare an array list to hold the data
ArrayList<Integer> list;
list = new ArrayList<Integer>();
int count = 0;
int num = 0;
int val = 0;
String line = "";
try
{
// create or append to the file
FileWriter fileOut = new FileWriter("outData.txt");
BufferedWriter fout = new BufferedWriter(fileOut);
System.out.println("how many data items?");
count = scan.nextInt();
for (int i = 1; i <= count; i++)
{
System.out.println("enter a data value");
val = scan.nextInt();
fout.write(val + " ");
}
System.out.println("thank you ... the data has been recorded!");
// close the output stream objects
fout.close();
fileOut.close();
scan.close();
}
catch(Exception e)
{
// catch an exception if any arises
System.err.println("Error: " + e.getMessage());
}
}
}
PROJECT Java File Processing Application: Java Data Analytics
STEP 3 Build, Compile and Run the Program
From the menu select [ Run ] and click [ Run Project ] to run your app.
STEP 4 Test the Program and Write the Data
Once you have successfully compiled your program enter a valid list of data values as shown below. Your initial program code will request a count of data values to be recorded and then write the data values to a text file.
[ Program Output ]
how many data items?
5
enter a data value
20
enter a data value
50
enter a data value
10
enter a data value
80
enter a data value
90
thank you . . . the data has been recorded!
STEP 5 Open the Data File and Review the Contents of the File
Within your software development environment, click [ File ] and then [ Open ] to review the contents of the data file that was created by running the program. Locate the outData.txt text file and open the file to view its contents.
STEP 6 Read the Data File
Once you have successfully compiled and tested your starter program and opened the text file with the data, you will now supplement your program with some program code that will read the data in the outData.txt text file and individually place the data values into a Java ArrayList .
Place the statements that are shown in Figure 2 before the closing curly brace
" } " of the try block.
PROJECT Java File Processing Application: Java Data Analytics
Figure 2 Additional Source Code for the Data Analytics File Processing Program
// read the data
FileReader fileIn = new FileReader("outData.txt");
BufferedReader fin = new BufferedReader(fileIn);
while ((line = fin.readLine()) != null)
{
num = Integer.parseInt(line);
list.add(num);
System.out.println(num);
}
System.out.println("thank you ... the data has been received!");
fin.close();
fileIn.close();
Save your program and run the program with the sample data that was given earlier. Observe the output of your program.
STEP 7 Supplement the Program Code Statements
Supplement again the program by including a method that displays the data that was recorded into the Java ArrayList .
Within your program, create a method named DisplayData() , which has this signature and definition. Place the method below the main() method and before the closing curly brace " } " of the class definition.
public static void DisplayData(ArrayList<Integer> num)
{
for (int i = 0; i < num.size(); i++)
System.out.println(num.get(i).toString());
}
Then, before the closing curly brace " } " of the try block, place these two statements.
System.out.println("display unsorted data");
DisplayData(list);
Save your program and run the program with the sample data that was given earlier.
Now include a method that will sort the data that was placed into the ArrayList . Place the method below the DisplayData() method and before the closing curly brace " } " of the class definition.
Use the Bubble Sort routine that follows in Figure 3 .
In an appropriate place in the main() method include these lines of code to show that the data has been sorted.
System.out.println("display sorted data");
DisplayData(list);
PROJECT Java File Processing Application: Java Data Analytics
Figure 3 Source Code for the Data Analytics File Processing Program
public static void BubbleSort(ArrayList<Integer> num)
{
int j = 0;
boolean flag = true; // set the flag to true to begin first pass
int temp = 0; // define the holding variable
while (flag)
{
flag = false; //set flag to false awaiting a possible swap
for (j = 0; j < num.size() - 1; j++)
{
if (num.get(j) > num.get(j + 1))
// for descending sort change to <
{
temp = num.get(j); //swap the elements
num.set(j, num.get(j + 1));
num.set(j + 1, temp);
flag = true; //shows a swap occurred
}
}
}
}
STEP 8 Modify the Program
After testing your program that it displays the original data in an unsorted order and a sorted order, modify again the program to include each of these variations:
• Add a new method named MaxMin() that will find the smallest and largest value in the ArrayList after the data has been sorted.
• Add a new method named Average() that will find the average value in the ArrayList after the data has been sorted.
• Add a new method named PerfectSquares() that will find any values in the ArrayList that are perfect squares, such as 36 or 121 .
Save your program and perform a trial run of it. Test your program with data similar to that shown below.
import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;
// Sammy Student: Data Analysis with Java File Processing
class DataAnalytics
{
public static void main(String args[])
{
// declare an object to receive the data
Scanner scan = new Scanner(System.in);
// declare an array list to hold the data
ArrayList<Integer> list;
list = new ArrayList<Integer>();
int count = 0;
int num = 0;
int val = 0;
String line = "";
try
{
// create or append to the file
FileWriter fileOut = new FileWriter("outData.txt");
BufferedWriter fout = new BufferedWriter(fileOut);
System.out.println("how many data items?");
count = scan.nextInt();
for (int i = 1; i <= count; i++)
{
System.out.println("enter a data value");
val = scan.nextInt();
fout.write(val + " ");
}
System.out.println("thank you ... the data has been recorded!");
// close the output stream objects
fout.close();
fileOut.close();
scan.close();
}
catch(Exception e)
{
// catch an exception if any arises
System.err.println("Error: " + e.getMessage());
}
}
}
Explanation / Answer
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.Scanner;
// Sammy Student: Data Analysis with Java File Processing
class DataAnalytics {
public static void main(String args[]) {
// declare an object to receive the data
Scanner scan = new Scanner(System.in);
// declare an array list to hold the data
ArrayList<Integer> list;
list = new ArrayList<Integer>();
int count = 0;
int num = 0;
int val = 0;
String line = "";
try {
// create or append to the file
FileWriter fileOut = new FileWriter("outData.txt");
BufferedWriter fout = new BufferedWriter(fileOut);
System.out.println("how many data items?");
count = scan.nextInt();
for (int i = 1; i <= count; i++) {
System.out.println("enter a data value");
val = scan.nextInt();
fout.write(val + " ");
}
System.out.println("thank you ... the data has been recorded!");
// close the output stream objects
fout.close();
fileOut.close();
scan.close();
// read the data
FileReader fileIn = new FileReader("outData.txt");
BufferedReader fin = new BufferedReader(fileIn);
while ((line = fin.readLine()) != null) {
num = Integer.parseInt(line);
list.add(num);
System.out.println(num);
}
System.out.println("thank you ... the data has been received!");
fin.close();
fileIn.close();
System.out.println("display unsorted data");
DisplayData(list);
BubbleSort(list);
System.out.println("display sorted data");
DisplayData(list);
MaxMin(list);
System.out.println("Average :" + Average(list));
System.out.println("Perfect Squares:");
PerfectSquares(list);
} catch (Exception e) {
// catch an exception if any arises
System.err.println("Error: " + e.getMessage());
}
}
/**
* to display the data
*
* @param num
*/
public static void DisplayData(ArrayList<Integer> num) {
for (int i = 0; i < num.size(); i++)
System.out.println(num.get(i).toString());
}
/**
* to sort the list
*
* @param num
*/
public static void BubbleSort(ArrayList<Integer> num) {
int j = 0;
boolean flag = true; // set the flag to true to begin first pass
int temp = 0; // define the holding variable
while (flag) {
flag = false; // set flag to false awaiting a possible swap
for (j = 0; j < num.size() - 1; j++) {
if (num.get(j) > num.get(j + 1))
// for descending sort change to <
{
temp = num.get(j); // swap the elements
num.set(j, num.get(j + 1));
num.set(j + 1, temp);
flag = true; // shows a swap occurred
}
}
}
}
/**
* that will find the smallest and largest value in the ArrayList after the
* data has been sorted.
*
* @param num
*/
public static void MaxMin(ArrayList<Integer> num) {
System.out.println("Min :" + num.get(0));
System.out.println("Max :" + num.get(num.size() - 1));
}
/**
* find the average value in the ArrayList after the data has been sorted.
*
* @param num
* @return
*/
public static double Average(ArrayList<Integer> num) {
int total = 0;
for (int i = 0; i < num.size(); i++) {
total += num.get(i);
}
return (double) total / num.size();
}
/**
* find any values in the ArrayList that are perfect squares,
*
* @param num
*/
public static void PerfectSquares(ArrayList<Integer> num) {
for (int i = 0; i < num.size(); i++) {
double sqrt = Math.sqrt(num.get(i));
int x = (int) sqrt;
if (Math.pow(sqrt, 2) == Math.pow(x, 2)) {
System.out.println(num.get(i) + " ");
}
}
System.out.println();
}
}
OUTPUT:
how many data items?
5
enter a data value
10
enter a data value
32
enter a data value
54
enter a data value
36
enter a data value
80
thank you ... the data has been recorded!
10
32
54
36
80
thank you ... the data has been received!
display unsorted data
10
32
54
36
80
display sorted data
10
32
36
54
80
Min :10
Max :80
Average :42.4
Perfect Squares:
36
outData.txt
10
32
54
36
80
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