The document contains Java code implementing a grocery item and a grocery list management system. The classes allow for adding, modifying, and displaying grocery items, as well as calculating the total cost and checking for the presence of items. It includes methods for traversal, insertion, and deletion of list nodes in a linked list structure.

1. Here is the code
import java.util.*;
class GroceryItem
{
String name;
double value;
GroceryItem(String n, double v)
{
name=n;
value=v;
}
void setName(String n)
{
name=n;
}
void setValue(double n)
{
if(n>0)
value=n;
else value=0;
}
String getName()
{
return name;
}
double getValue()
{
return value;
}
public String toString()
{

2. return "Name: "+name+", Price: "+value;
}
boolean equals(GroceryItem m)
{
if(this.name.equals(m.name) && this.value==m.value) return true;
else return false;
}
}
public class GroceryList
{
class ListNode
{
GroceryItem data;
ListNode link;
ListNode(GroceryItem i)
{
data=i;
link=null;
}
ListNode()
{
data=null;
link=null;
}
}
ListNode head, current, previous;
GroceryList()
{
head=null;
current=head;
previous=head;

3. }
void addItem(String s, double v)
{
ListNode n=new ListNode(new GroceryItem(s,v));
if(head==null)
{
head=n;
}
else if(head.link==null)
{
head.link=n;
}
else
{
ListNode t=head;
while(t.link!=null)
{
t=t.link;
}
t.link=n;
}
}
void goToNext()
{
if(current.link!=null)
{
previous=current;
current=current.link;
}
}

4. String getDataAtCurrent()
{
return current.data.toString();
}
void setDataAtCurrent(GroceryItem n)
{
if(current!=null)
{
current.data.setName(n.getName());
current.data.setValue(n.getValue());
}
}
void insertAfterCurrent(GroceryItem m)
{
if(current!=null)
{
ListNode n= new ListNode(m);
n.link=current.link;
current.link=n;
System.out.println("Node Added");
}
}
void deleteCurrentNode()
{
if(current!=null)
{
previous.link=current.link;
}
}
void showList()
{
ListNode t=head;
while(t!=null)
{
System.out.println(t.data+" ");

5. t=t.link;
}
System.out.println("Done! ");
}
boolean contains(String n, double v)
{
ListNode t=head;
GroceryItem i = new GroceryItem(n,v);
while(t!=null)
{
if(t.data.equals(i))
{
return true;
}
else t=t.link;
}
return false;
}
double totalCost()
{
ListNode t=head;
double cost=0;
while(t!=null)
{
cost+=t.data.getValue();
t=t.link;
}
return cost;
}
public static void main(String a[])
{

6. System.out.println("Grocery List Tester");
System.out.println("Creating Grocery List");
GroceryList l = new GroceryList();
System.out.println("Adding 5 grocery items");
l.addItem("Taco Shells", 2.0);
l.addItem("Salsa", 1.59);
l.addItem("Ground Beef", 4.59);
l.addItem("Taco Shells", 1.3);
l.addItem("Shredded Cheese", 2.99);
l.showList();
System.out.println("Do I remember the salsa? "+l.contains("Salsa", 1.59));
System.out.println("Total Cost "+l.totalCost());
}
}
Solution
Here is the code
import java.util.*;
class GroceryItem
{
String name;
double value;
GroceryItem(String n, double v)
{
name=n;
value=v;

7. }
void setName(String n)
{
name=n;
}
void setValue(double n)
{
if(n>0)
value=n;
else value=0;
}
String getName()
{
return name;
}
double getValue()
{
return value;
}
public String toString()
{
return "Name: "+name+", Price: "+value;
}
boolean equals(GroceryItem m)
{
if(this.name.equals(m.name) && this.value==m.value) return true;
else return false;
}
}
public class GroceryList
{

8. class ListNode
{
GroceryItem data;
ListNode link;
ListNode(GroceryItem i)
{
data=i;
link=null;
}
ListNode()
{
data=null;
link=null;
}
}
ListNode head, current, previous;
GroceryList()
{
head=null;
current=head;
previous=head;
}
void addItem(String s, double v)
{
ListNode n=new ListNode(new GroceryItem(s,v));
if(head==null)
{
head=n;
}
else if(head.link==null)
{

9. head.link=n;
}
else
{
ListNode t=head;
while(t.link!=null)
{
t=t.link;
}
t.link=n;
}
}
void goToNext()
{
if(current.link!=null)
{
previous=current;
current=current.link;
}
}
String getDataAtCurrent()
{
return current.data.toString();
}
void setDataAtCurrent(GroceryItem n)
{
if(current!=null)
{
current.data.setName(n.getName());
current.data.setValue(n.getValue());
}
}

10. void insertAfterCurrent(GroceryItem m)
{
if(current!=null)
{
ListNode n= new ListNode(m);
n.link=current.link;
current.link=n;
System.out.println("Node Added");
}
}
void deleteCurrentNode()
{
if(current!=null)
{
previous.link=current.link;
}
}
void showList()
{
ListNode t=head;
while(t!=null)
{
System.out.println(t.data+" ");
t=t.link;
}
System.out.println("Done! ");
}
boolean contains(String n, double v)
{
ListNode t=head;
GroceryItem i = new GroceryItem(n,v);
while(t!=null)
{
if(t.data.equals(i))

11. {
return true;
}
else t=t.link;
}
return false;
}
double totalCost()
{
ListNode t=head;
double cost=0;
while(t!=null)
{
cost+=t.data.getValue();
t=t.link;
}
return cost;
}
public static void main(String a[])
{
System.out.println("Grocery List Tester");
System.out.println("Creating Grocery List");
GroceryList l = new GroceryList();
System.out.println("Adding 5 grocery items");
l.addItem("Taco Shells", 2.0);
l.addItem("Salsa", 1.59);
l.addItem("Ground Beef", 4.59);
l.addItem("Taco Shells", 1.3);
l.addItem("Shredded Cheese", 2.99);

12. l.showList();
System.out.println("Do I remember the salsa? "+l.contains("Salsa", 1.59));
System.out.println("Total Cost "+l.totalCost());
}
}