Question

Objectives In this lab you will review passing arrays to methods and partially filled arrays. Requirements 1. Fill an array with data from an input file sampledata-io.txt (Attached) a. Assume no more than 100 data items, terminated by -1 for sentinel b. Note that the sample data file has other information after the sentinel; it should cause no problem c. Read and store data d. Print the number of data stored in the array e. Add a method to reverse the array. Pass the original array as the argument and return the reversed array. 2. Testing a. Invoke the reverse method, print out the reversed array. 3. Inserting into the partially filled array a. Add a method to insert a user inputted value into a specific location. b. Remember to check parameters for validity. Also remember to check whether the array is full or not. c. Invoke the insert method, prompt to user whether the insertion is successful or not. 4. Removing from the partially filled array a. Add a method to remove the element at the specific location in the partially filled array. b. Invoke the remove method, prompt to user whether the remove is successful or not. If the remove is successful, print out the value of the element just removed. There are several important points that are general requirements for labs in this course: ♣ Include a comment at the beginning of each source file you submit that includes your name and the lab date. ♣ Names for variables and other program components should be chosen to help convey the meaning of the variable. ♣ Turn in an archive of the entire Eclipse project for each lab. Do not attempt to turn in individual files, some course management systems mangle such files.

Answer 1

package myProject;
import java.util.*;
import java.io.File;
//Create a class Array Operation
public class ArrayOperation
{
   //Initializes the counter to zero
   int counter = 0;

   //Method to read data from file
   void readData(int numberArray[])
   {
       //File object created
       File file = new File("D:/TODAY/src/myProject/data.txt");
      
       //Handles exception      
       try
       {
           //Scanner object created
           Scanner scanner = new Scanner(file);
           //Checks for the data availability
           while(scanner.hasNextInt())
           {
               //Reads a number from the file
               int no = scanner.nextInt();
               //Checks if the number is -1 then stop reading
               if(no == -1)
                   break;
               //Stores the number in the array
           numberArray[counter++] = no;
           }//End of while
       }//End of try

       //Catch block
       catch(Exception e)
       {
           e.printStackTrace();
       }//End of catch

       //Displays number of elements present in the array
       System.out.println("Numbers of data stored in array = " + counter);
   }//End of method
  
   //Method to display the array in reverse order
   void displayReverse(int numberArray[])
   {
       System.out.println("Numbers in reverse order: ");

       //Loops from end to beginning and displays the elements in reverse order
       for(int i = counter - 1; i >= 0 ; i--)
               System.out.print(numberArray[i] + " ");
   }
  
   //Displays the contents of the array
   void displayArray(int numberArray[])
   {
       //Loops from beginning to end and displays the array contents
       for(int c = 0; c < counter; c++)
           System.out.print(numberArray[c] + " ");
   }
  
   //Returns the status of insertion operation
   boolean insertSpecifiedLocation(int numberArray[])
   {
       //Initializes the status to false
       boolean status = false;

       //Loop variable
       int c;
      
       //Scanner class object created
       Scanner scanner = new Scanner(System.in);
      
       //Accepts the position and number for insertion
       System.out.println("\nEnter the poistion to insert a number: ");
       int position = scanner.nextInt();
       System.out.println("Enter the a number to insert at position: " + position);
       int number = scanner.nextInt();

       //Checks the validity of the position
       if(position >= 0 && position < counter)
       {
           //Checks the overflow condition
           if(counter > 99)
               System.out.println("Error: Overflow Memory, Array is full");
          
           else
           {
               //Loops from end of the array to the position specified.
               //position - 1 because array index position starts from 0
               for(c = counter - 1; c >= position - 1; c--)
                   //Shifting the values to next position till the position specified
                   numberArray[c + 1] = numberArray[c];
              
               //Stores the number in the specified position. position - 1 because array index position starts from 0
               numberArray[position - 1] = number;
              
               //Increase the length of the array by 1
               counter++;
              
               //Update the status to true for successful insertion
               status = true;
           }//end of else
       }//End of if
       //Displays error message
       else
           System.out.println("Error: Invalid Position");
      
       //Returns the status
       return status;
   }//End of method
  
   //Method removes a number from a specified position and returns the status
   boolean removeSpecifiedLocation(int numberArray[])
   {
       //Initializes the status to false
       boolean status = false;
      
       //Loop variable
       int c;
      
       //scanner class object created
       Scanner scanner = new Scanner(System.in);
      
       //Accept the position to remove the number
       System.out.println("\nEnter the poistion to remove a number: ");
       int position = scanner.nextInt();
      
       //Checks the validity of the position
       if(position >= 0 && position < counter)
       {
           //If the length is zero no more element to be deleted
           if(counter == -1)
               System.out.println("Error: Underflow Memory, Array is empty");
           else
           {
               //Displays the removed element
               System.out.println("Removed element: " + numberArray[position - 1]);
              
               //Loops from the specified position to the length of the array.
               //position - 1 because array index position starts from 0
               for(c = position - 1; c < counter; c++)
                   //Shifting the next position value to the current position till the position specified
                   numberArray[c] = numberArray[c + 1];
              
               //Decrease the length by 1
               counter--;

               //Update the status to true for successful deletion
               status = true;
           }//End of else
       }//End of if

       //Displays error message
       else
           System.out.println("Error: Invalid Position");
      
       //Returns the status
       return status;
   }//End of method
  
   //Method to display menu
   void menu()
   {
       System.out.println("\n1) Display Reverse order");
       System.out.println("2) Insert a number into a specified position");
       System.out.println("3) Remove a number from specified position");
       System.out.println("4) Exit");
   }
  
   //Main method to test
   public static void main(String ss[])
   {
       //Creates an array of size 100
       int numberArray [] = new int[100];
      
       //status to check success of failure
       boolean status;
      
       //To store user choice
       int ch;
      
       //Scanner class object created
       Scanner scanner = new Scanner(System.in);
      
       //Creates ArrayOperation class object
       ArrayOperation ao = new ArrayOperation();
      
       //Call readData to read data from file
       ao.readData(numberArray);
      
       //Loops till user choice
       do
       {
           //Calls menu method to display menu
           ao.menu();

           //Accepts user choice
           System.out.println("\n Enter your choice: ");
           ch = scanner.nextInt();
          
           switch(ch)
           {
               //To display in reverse order
               case 1:
                   ao.displayReverse(numberArray);
                   break;
                  
               //To insert a number at specified position
               case 2:
                   status = ao.insertSpecifiedLocation(numberArray);

                   //If the status is true Display the array
                   if(status)
                   {
                       System.out.println("Insertion successfull \n After Insertion: ");
                       ao.displayArray(numberArray);      
                   }
                   break;

               //To Remove an element
               case 3:
                   status = ao.removeSpecifiedLocation(numberArray);
                   //If the status is true Display the array
                   if(status)
                   {
                       System.out.println("Deletion successfull \n After Deletion: ");
                       ao.displayArray(numberArray);
                   }
                   break;

               //Exit the program
               case 4:
                   System.out.println("Thank You");
                   System.exit(0);                  
               default:
                   System.out.println("Invalid Choice");
           }   //End of switch
       }while(true);      
   }//End of main method  
}//End of class

Output:

Numbers of data stored in array = 8

1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
1
Numbers in reverse order:
66 45 56 80 50 30 20 10
1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
2

Enter the poistion to insert a number:
12
Enter the a number to insert at position: 12
66
Error: Invalid Position

1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
2

Enter the poistion to insert a number:
3
Enter the a number to insert at position: 3
88
Insertion successfull
After Insertion:
10 20 88 30 50 80 56 45 66
1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
3

Enter the poistion to remove a number:
56
Error: Invalid Position

1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
3

Enter the poistion to remove a number:
1
Removed element: 10
Deletion successfull
After Deletion:
20 88 30 50 80 56 45 66
1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
3

Enter the poistion to remove a number:
4
Removed element: 50
Deletion successfull
After Deletion:
20 88 30 80 56 45 66
1) Display Reverse order
2) Insert a number into a specified position
3) Remove a number from specified position
4) Exit

Enter your choice:
4
Thank You