Question

Objective: Text File I/0 and Regular Expressions Note that both classes below should handle all exceptions that might be thrown within them. 1. Create a class that does the following: a. Reads the name of a file to create as the first command line argument. (Overwrite any file with the same name). b. Reads an integer value as the second command line argument. C. The program should generate as many random numbers as are specified in the second command line argument (from step b) with magnitudes between 1 and 1000 (both inclusive) and write them to the file. Use a seed of 152 for your random number generator. d. You must write only 5 numbers on each line and then begin a new line. (The last line may have less than 5 numbers.) Delimit the numbers on a line with the & character. The end of a line should be delimited by the # character. No other delimiters should be explicitly used. A sample output file for 12 numbers might look like this: 19834&4&235&6# 1278524840085&611# 55&2# 2. Create a second class that does the following: a. Reads the name of the file to open as a command line argument. (Check for incorrect usage). b. Reads in all of the numbers from that file using a Scanner. (Assume a file format identical to the file created in (1) and make sure you use regular expressions to specify the delimiter.) c. Displays, to the standard output, the count and average of all of those numbers.

Answer 1

Below are the Java programs to create a file having random numbers (FileWrite.java) and read that file and display count and average of the numbers(FileReadScanner.java).

Copy the below files in your editor and test.

FileWrite.java

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStreamWriter;

import java.util.Random;

public class FileWrite {

public static void main(String args[]) throws IOException {

String fileName = args[0];

int numCount = Integer.parseInt(args[1]);

File fout = new File(fileName);

FileOutputStream fos = new FileOutputStream(fout);

BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));

int i = 0;

while (i < numCount) {

int j = 0;

StringBuffer buffer = new StringBuffer();

while (j < 5 && i< numCount) {

int randomNum = getRandomNumberInRange(1, 1000);

buffer.append(randomNum);

if (j != 4 && i != numCount -1)

buffer.append("&");

j++;

i++;

}

buffer.append("#");

bw.write(buffer.toString());

bw.newLine();

}

bw.close();

}

private static int getRandomNumberInRange(int min, int max) {

if (min >= max) {

throw new IllegalArgumentException("max must be greater than min");

}

Random r = new Random();

return r.nextInt((max - min) + 1) + min;

}

}

FileReadScanner.java

import java.io.File;

import java.io.IOException;

import java.util.Scanner;

import java.util.regex.Pattern;

public class FileReadScanner {

public static void main(String args[]) throws IOException {

String fileName;

fileName = args[0];

File file = new File(fileName);

Scanner sc = new Scanner(file);

int count=0,sum =0;

while (sc.hasNextLine() ) {

String line = sc.nextLine();

String[] output = line.split(Pattern.quote("&"));

for(String s: output){

count++;

if(s.contains("#")){

s= s.substring(0, s.length()-1);

}

sum +=Integer.parseInt(s);

System.out.println(s);

}

}

sc.close();

System.out.println("Count of numbers is :" + count);

System.out.println("Average of numbers is :" + (sum/count));

}

}

Output :

623
939
357
193
86
918
469
566
605
Count of numbers is :9
Average of numbers is :528

import java.io.File; import java.io.IOException; import java.util.Scanner; import java.util.regex.Pattern; public class FileReadScanner { public static void main(String args[]) throws IOException i String fileName;l fileName args[e]; File file = new File (fileName); Scanner sc = new Scanner(file); int count=0, sum =0; while (sc.hasNextLine() ) 5 string line = sc.next Line(); String] output - line.split(Pattern.quote("&")); for(String s: output)I count+t; ifis.contains("#"))( s-S.substring(0, s.length)-1); sum Integer.parseInt(s); System.out.println (s); sc.close); System.out.println( "Count of numbers is :" count); System.out.println("Average of numbers is :" + (sum/count));

e> FileReadScanner ava Applic 623 939 357 193 86 918 469 566 605 Count of numbers is:9 Average of numbers is :528