Question

in java please

Create a command line program

Add an array that stores 20 integers
Fill the array with random integers between 1 and 1000.
Display the values in the array to stdout (the screen). Include a message explaining what is being displayed.
Save the values in the array to a text file.
Read the values stored in the text file to stdout (the screen). Include a message explaining what is being displayed.

Answer 1

import java.util.*;
import java.io.*;
public class Main
{
   public static void main(String[] args) {
   int []a=new int[20];
   int i;
   String file1="input.txt";//store file name
   Random rand=new Random();//random class
   for(i=0;i<20;i++)
   {
   a[i]=rand.nextInt(1000);//genrate random numbers
   }
   System.out.println("Values from array");
   for(i=0;i<20;i++)
   System.out.print(a[i]+" ");//print numbers from array
   System.out.println();
   try(FileWriter fw = new FileWriter(file1))//open file to write with FileWriter
   {
for(i=0;i<20;i++)
fw.write(a[i]);//write the values
}
catch (IOException e)//catch i/o Exceptions here
{
System.out.println("I/O Error"+e);
}
System.out.println("The values from file");
       try(FileReader fr = new FileReader(file1)) {//FileReader to read file contents
int ch = fr.read();//read each value
while(ch!=-1) {
System.out.print(ch+" ");//print it to output
ch=fr.read();
}
}
catch (FileNotFoundException e) //exceptions
{
System.out.println("File not found"+e);
}
catch (IOException e)
{
System.out.println("I/O Error"+e);
}
   }
}

In file which we are storing this values contains special characters but not in original way because while reading if we have 132 as one number it reads 1 first and prints it's ascii and then 3 and after 2.So,if it stored in it's own way then we will get exact same values while reading