Question

Purse

1. Implement a class Purse. A purse contains a collection of coins. For simplicity, we will only store the coin names in an ArrayList<String>.

a. Supply a method

void addcoin(String coinName)

that adds a coin to the purse.

b. Write a method toString() to the Purse class that prints the coins in the purse in the format

Purse[Quarter, Dime, Nickel, Dime]

2. Write a method reverse that reverses the sequence of coins in a purse. Use the toString method of the preceding assignment to test your code. For example, if reverse is called with a purse

Purse[Quarter, Dime, Nickel, Dime]

Then the purse is changed to

Purse[Dime, Nickel, Dime, Quarter]

3. Write a method for the Purse class,

public void transfer(Purse other)

that transfers the contents of one purse to another. For example, if a is

Purse[Quarter, Dime, Nickel, Dime]

and b is

Purse[Dime, Nickel]

then after the call, a.transfer(b), a is

Purse[Quarter, Dime, Nickel, Dime, Dime, Nickel]

and b is empty.

4. Write a method for the Purse class

public boolean sameContents(Purse other)

That checks whether the other purse has the same coins in the same order.

5. Write a method

public boolean sameCoins(Purse other)

that checks whether the other purse has the same coins, perhaps in a different order. For example, the purses

Purse[Quarter, Dime, Nickel, Dime]

and

Purse[Nickel, Dime, Dime, Quarter]

should be considered equal. You will probably need one or more helper methods.

Answer 1

Screenshot

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Program

import java.util.ArrayList;
//Create a class Purse
class Purse{
   //Member variable
   private ArrayList<String> coins;
   //default constructor
   public Purse() {
       coins=new ArrayList<String>();  
   }
   //Method to add coins in the purse
   void addcoin(String coinName) {
       coins.add(coinName);
   }
   //Meethod to print Purse contents
   public String toString() {
       String str="Purse[";
       for(int i=0;i<coins.size();i++) {
           if(i<coins.size()-1) {
               str+=coins.get(i)+",";
           }
           else {
               str+=coins.get(i);
           }
       }
       str+="]";
       return str;
   }
   //Method to reverse the purse contents order
   public void reversePurse() {
       ArrayList<String>newArrayList=new ArrayList<String>();
       for(int i=coins.size()-1;i>=0;i--) {
           newArrayList.add(coins.get(i));
       }
       coins=newArrayList;
   }
   //Method to transfer data from one purse to other
   //remove coins from the other purse
   public void transfer(Purse other) {
       for(int i=0;i<other.coins.size();i++) {
           this.coins.add(other.coins.get(i));
       }
       other.coins.clear();
   }
   //Check the contents of other purse has same contents in same order
   public boolean sameContents(Purse other) {
       if(coins.size()!=other.coins.size()) {
           return false;
       }
       else {
           for(int i=0;i<coins.size();i++) {
               if(!coins.get(i).equals(other.coins.get(i))){
                   return false;
               }
           }
           return true;
       }
   }
   //Method to same contents in two purse
   public boolean sameCoins(Purse other) {
       if(coins.size()!=other.coins.size()) {
           return false;
       }
       else {
           if(coins.containsAll(other.coins) && other.coins.containsAll(coins)) {
               return true;
           }
           else {
               return false;
           }
        }
     }
}
//Test class
public class PurseTest {

   public static void main(String[] args) {
       //Creaate a purse object
       Purse p=new Purse();
       //Add coins into the purse
       p.addcoin("Quarter");
       p.addcoin("Dime");
       p.addcoin("Nickel");
       p.addcoin("Dime");
       //Display purse contents
       System.out.println("Contents of the purse: "+p);
       //Reverse the purse
       p.reversePurse();
       //Display purse contents
       System.out.println("Contents of the purse after reverse: "+p);
       //Create another purse
       Purse p1=new Purse();
       //Add coins
       p1.addcoin("Dime");
       p1.addcoin("Nickel");
       //Display contents
       System.out.println("Contents of the two purses before transfer:");
       System.out.println(p);
       System.out.println(p1);
       p.transfer(p1);
       System.out.println("Contents of the two purses after transfer:");
       System.out.println(p);
       System.out.println(p1);
       //Create another purse
       p1=new Purse();
       //add coins
       p1.addcoin("Dime");
       p1.addcoin("Nickel");
       p1.addcoin("Dime");
       p1.addcoin("Quarter");
       //Check both has same content in same order
       if(p.sameContents(p1)) {
           System.out.println("P and p1 has same contents!!!");
       }
      
       else {
           System.out.println("P and p1 has not same contents!!!");
       }
       //Check both has same coins
       //Creaate a purse object
               Purse p2=new Purse();
               //Add coins into the purse
               p2.addcoin("Quarter");
               p2.addcoin("Dime");
               p2.addcoin("Nickel");
               p2.addcoin("Dime");
               if(p1.sameCoins(p2)) {
                   System.out.println("P1 and p2 has same coins!!!");
               }
              
               else {
                   System.out.println("P1 and p2 has not same coins!!!");
               }
               //Check for no change
               System.out.println("Display purse p2 after operation: "+p2);
   }

}

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Output

Contents of the purse:
Purse[Quarter,Dime,Nickel,Dime]
Contents of the purse after reverse:
Purse[Dime,Nickel,Dime,Quarter]
Contents of the two purses before transfer:
Purse[Dime,Nickel,Dime,Quarter]
Purse[Dime,Nickel]
Contents of the two purses after transfer:
Purse[Dime,Nickel,Dime,Quarter,Dime,Nickel]
Purse[]
P and p1 has not same contents!!!
P1 and p2 has same coins!!!
Display purse p2 after operation:
Purse[Quarter,Dime,Nickel,Dime]