Question

/*
* File: ListDriver.java
* Assignment: Lab03
* Author:
* Date:
* Course:
* Instructor:
*
* Purpose: Test an implementation of an array-based list ADT.
* To demonstrate the use of "ListArrayBased" the project driver
* class will populate the list, then invoke various operations
* of "ListArrayBased".
*/
import java.util.Scanner;

public class ListDriver {

   /*
   * main
   *
   * An array based list is populated with data that is stored
   * in a string array. User input is retrieved from that std in.
   * A text based menu is displayed that contains a number of options.
   * The user is prompted to choose one of the available options:
   * (1) Build List, (2) Add item, (3) Remove item, (4) Remove all items,
   * or (5) done. The switch statement manages calling the
   * appropriate method based on the option chosen by the user, and
   * prompts the user for further input as required Program terminates
   * if user chooses option (5). If the user chooses an option that is
   * not in the menu, a message telling the user to choose an appropriate
   * option is written to std out, followed by the options menu.
   */
   public static void main(String[] args)
   {
       String[] dataItems = {"milk","eggs","butter","apples","bread","chicken"};

       // TO DO: add code here
              
   } // end of main method
  
   /*
   * Displays the options menu, including the prompt
   * for the user
   */
   public void displayMenu()
   {
       // TODO: add code here
   }
  
   /*
   * displayStatus
   *
   * displays information about the state of
   * the list
   *
   * Preconditions: a reference to a list
   *
   * Postconditions:
   * "List empty: B" where B is either TRUE or FALSE
   * and "Size of list: n" where n is the size of
   * the list is written to std out.
   */
   public void displayStatus(ListArrayBased list)
   {
       // TO DO: add code here
   }
  
   /*
   * displayList
   *
   * Precondition: a reference to a list
   *
   * Postcondition: list is displayed on std out
   */
   public void displayList(ListArrayBased list)
   {
       // TO DO: add code here
   }
  
   /*
   * buildList
   *
   * Precondition: a reference to a list and an string array
   * of items to be address to the list
   *
   * Postcondition: items stored the string array are added
   * to the list.
   */
   public void buildList(ListArrayBased list, String[] items)
   {
       // TO DO: add code here
   }

   /*
   * addItem
   *
   * Precondition: a reference to a list, a String
   * representing a grocery item, and the integer
   * pos is the position in the list
   *
   * Postcondition: an item is added to the list at
   * position pos.
   */
   public void addItem(ListArrayBased list, String item, int pos)
   {          
       // TO DO: add code here      
   }
  
   /*
   * removeItem
   *
   * Precondition: a reference to a list and
   * int pos;
   *
   * Postcondition: item is removed from the list by its
   * position pos.
   */
   public void removeItem(ListArrayBased list, int pos)
   {      
       // TO DO: add code here      
   }
  
   /*
   * removeAllItems
   *
   * Precondition: a reference to a list
   *
   * Postcondition: all items currently stored in the list
   * are removed
   */
   public void removeAllItems(ListArrayBased list)
   {
       // TO DO: add code here
   }
      
} // end of class ListArrayBasedDriver

Answer 1

/////////////////////////////////////////////// ListArrayBased.java

public class ListArrayBased {
   private String [] itrms;// array of string
   private int index;// current index
   private int size;// size of array
  
   // constructor
   public ListArrayBased(int n){
       this.itrms=new String[n];
       this.size=n;
       // initialize
       for(int i=0;i<n;i++){
           this.itrms[i]="";
       }
       this.index=-1;
   }
  
   // set value at position pos
   public void setValue(String str,int pos){
       if(this.index<this.size){
           this.itrms[pos]=str;
           this.index++;
       }      
   }
  
   // add value at position pos
   public void addValue(String str,int pos){
       if(this.index<this.size){
           // increase the positional value
           // a b c
           // n a b c [ a b c increase positioned ]
           for(int i=this.index;i>pos;i--){
               this.itrms[i]=this.itrms[i-1];
           }
           this.itrms[pos]=str;
           this.index++;
       }      
   }
  
   // get value at position pos
   public String getValue(int pos){
       return(this.itrms[pos]);
   }
  
   // remove value at position pos
   public String removeAt(int pos){
       String ret="";
       if(this.index>-1){
           // get element from position
           ret=this.itrms[pos];
          
           // decrease the positional value
           for(int i=pos;i<this.index;i++){
               this.itrms[i]=this.itrms[i+1];
           }
           // decrease elements number
           this.index--;          
       }      
       return ret;
   }
  
   // remove all elements
   public void removeAll(){
       String ret="";
       this.index=-1;
   }
  
   // get current size
   public int getCurSize(){
       return this.index+1;
   }
  
   // if size is empty or not
   public boolean isEmpty(){
       return this.index==-1;
   }
}

////////////////////////////////////////////// ListDriver.java

/*
* File: ListDriver.java
* Assignment: Lab03
* Author:
* Date:
* Course:
* Instructor:
*
* Purpose: Test an implementation of an array-based list ADT.
* To demonstrate the use of "ListArrayBased" the project driver
* class will populate the list, then invoke various operations
* of "ListArrayBased".
*/
import java.util.Scanner;

public class ListDriver {

/*
* main
*
* An array based list is populated with data that is stored
* in a string array. User input is retrieved from that std in.
* A text based menu is displayed that contains a number of options.
* The user is prompted to choose one of the available options:
* (1) Build List, (2) Add item, (3) Remove item, (4) Remove all items,
* or (5) done. The switch statement manages calling the
* appropriate method based on the option chosen by the user, and
* prompts the user for further input as required Program terminates
* if user chooses option (5). If the user chooses an option that is
* not in the menu, a message telling the user to choose an appropriate
* option is written to std out, followed by the options menu.
*/
public static void main(String[] args)
{
String[] dataItems = {"milk","eggs","butter","apples","bread","chicken"};
ListArrayBased list=new ListArrayBased (20);
Scanner sc= new Scanner(System.in);

for(;;){
   // show status
   displayStatus(list);
   // show list
   displayList(list);
   // show menu
   displayMenu();
   System.out.print("Enter option : ");
   int option=sc.nextInt();
   // for wrong option
   if(option<1 || option>5){
       System.out.print("Wrong option , please choose correct option");
   }
   else{
       // each option
       if(option==1){
           buildList(list,dataItems);
       }
       if(option==2){
           System.out.print("Enter value : ");
           String str=sc.next();
           addItem(list,str,list.getCurSize());               
       }
       if(option==3){
           System.out.print("Remove at : ");
           int pos=sc.nextInt();
           removeItem(list,pos);
       }
       if(option==4){
           removeAllItems(list);
       }
       if(option==5){
           break;
       }
   }
     
}
  
} // end of main method
  
/*
* Displays the options menu, including the prompt
* for the user
*/
public static void displayMenu()
{
   System.out.println("1) Build List");
   System.out.println("2) Add item");
   System.out.println("3) Remove item");
   System.out.println("4) Remove all items");
   System.out.println("5) done");
     
}
  
/*
* displayStatus
*
* displays information about the state of
* the list
*
* Preconditions: a reference to a list
*
* Postconditions:
* "List empty: B" where B is either TRUE or FALSE
* and "Size of list: n" where n is the size of
* the list is written to std out.
*/
public static void displayStatus(ListArrayBased list)
{
   System.out.println("List Empty : "+list.isEmpty());
   System.out.println("Size of List : "+(list.getCurSize()));
}
  
/*
* displayList
*
* Precondition: a reference to a list
*
* Postcondition: list is displayed on std out
*/
public static void displayList(ListArrayBased list)
{
for(int i=0;i<list.getCurSize();i++){
   System.out.println("Element "+(i)+" : "+list.getValue(i));
}
}
  
/*
* buildList
*
* Precondition: a reference to a list and an string array
* of items to be address to the list
*
* Postcondition: items stored the string array are added
* to the list.
*/
public static void buildList(ListArrayBased list, String[] items)
{
   int curSize=list.getCurSize();
for(int i=0;i<items.length;i++){
   list.setValue(items[i], i+curSize);
}
}

/*
* addItem
*
* Precondition: a reference to a list, a String
* representing a grocery item, and the integer
* pos is the position in the list
*
* Postcondition: an item is added to the list at
* position pos.
*/
public static void addItem(ListArrayBased list, String item, int pos)
{
   list.addValue(item, pos);
}
  
/*
* removeItem
*
* Precondition: a reference to a list and
* int pos;
*
* Postcondition: item is removed from the list by its
* position pos.
*/
public static void removeItem(ListArrayBased list, int pos)
{
list.removeAt(pos);
}
  
/*
* removeAllItems
*
* Precondition: a reference to a list
*
* Postcondition: all items currently stored in the list
* are removed
*/
public static void removeAllItems(ListArrayBased list)
{
list.removeAll();
}
  
} // end of class ListArrayBasedDriver

///////////////////////////////////////////