Test 2  Name _______________     __/85

1. (12) What is the value or ranges produced from the following?

a. Random rM = new Random(); ______________
System.out.println( rM.nextInt(10) );

b. Random rM = new Random(); ______________
System.out.println( rM.nextInt(11) - 5 );

c. Random rM = new Random(); ______________
System.out.println( car [ rM.nextInt(4) ] );

d. Random rM = new Random(); ______________
System.out.println( rM.nextInt(10) + rM.nextInt(5) );

e. String name = “Marty”;
name.startsWith(“mar”); ______________

f. String name = “Marty”;
name.toLowerCase().startsWith(“mar”); ______________

2. (30) Use definitions on last page. What is the output of the following?

a. for ( int i=0; i < direction.length; i++ ) ______________
System.out.print ( direction[ i ] );

b. for ( int i=0; i < car.length; i++ ) ______________
     if ( car[ i ] >= 0 )
System.out.print ( car[ i ] );

c. for ( int i=notes.size()-1; i>0; i-- ) ______________
System.out.print ( notes.get( i ) );

d. TicketMachine tm = new TicketMachine(50);
for (int i=1; i<=3; i++)
tm.insertMoney( 10 ); ______________
tm.printTicket();

e. TicketMachine tm = busLine.get(“yellow”);
tm.insertMoney(20);
tm.printTicket(); ______________

f. int sum = 0;
for ( int i=0; i < car.length; i++ ) ______________
if ( car[ i ] >= 0 )
sum = sum + car[ i ];
System.out.print ( sum / car.length );

g. for (int i=0; i<3; i++) ______________
for (int j=i; j>0; j--)
System.out.print( i + “ “ + j );

h. int i=car.length-1;
while ( i >= 0 && car[ i ] > 0) ______________
{
System.out.print( car[ i ] );
i--;
}

i. for(int i=0; i<busTerminal.length; i++) ______________
{
busTerminal[i].insertMoney(70);
System.out.print(busTerminal[i].refundBalance() );
}

j. Iterator in = notes.iterator(); ______________
while( in.hasNext() )
System.out.print( in.next() );

3. (5) Draw the object diagram for the following:

TicketMachine t0, t1, t2;
HashMap <String, TicketMachine> machines = new HashMap<String, TicketMachine> ();
t0=new TicketMachine(50);
t1=new TicketMachine(25);
t2=new TicketMachine(40);
machines.put("50 Cents", t0);
machines.put("25 Cents", t1);
machines.put("40 Cents", t2);

4. (12) Give the definition for the following array, ArrayList and HashMaps.

a) Define an array named rhymes of type char initialized to contain the chars ‘b’, ‘c’, ‘d’, ‘e’, ‘p’, ‘z’.

b) Define an ArrayList collection named subway that references TicketMachine objects with price 40, 20, and 50 cents.

c) Define a HashMap collection named opposites that maps “day” to “night”, “large” to “small”, and “Republican” to “Democrat”.

5. (5) Define a TicketMachine emptyMachine method that returns the value of total field and sets total to zero.

6. (21) For the class Subway below:

1. Add a field named tm that can reference TicketMachine objects. Define tm as either an array, an ArrayList or a HashMap.
   
   
2. Define a constructor with no parameters that initializes the tm field to TicketMachine objects with price 40, 20, and 50 cents.
   
   
3. Define a constructor with signature public Subway(int n) that initializes the tm field to n TicketMachine objects with price 50 cents.
   
   
4. Define the method emptyAllMachines with no parameters that returns the sum of the total in all TicketMachines referenced by tm. Hint: Use an external call to your emptyMachine method.
   
   
5. Define the method insertRandomMoney with no parameters that randomly inserts between 5 and 30 cents into each TicketMachine referenced by tm. Hint: Use an external call to the insertMoney method of TicketMachine.

public class Subway
{
a)
ArrayList <TicketMachine> tm = new ArrayList <TicketMachine> ();

b)
public Subway() {
tm.add( new TicketMachine(40 ) );
tm.add( new TicketMachine(20 ) );
tm.add( new TicketMachine(50 ) );
}

c)
public Subway(int n) {
for (int i=0; i<n; i++)
tm.add( new TicketMachine(50 ) );
}
d)
public int emptyAllMachines() {
int total = 0;
for (int i=0; i<tm.size(); i++)
total = total + ( tm.get(i)).emptyMachine();
return total;
}
e)
public void insertRandomMoney() {
Random im = new Random();
for (int i=0; i<tm.size(); i++)
tm.get(i).insertMoney(im.nextInt(26)+5);
}

}

public class TicketMachine
{
private int price;
private int balance;
private int total;

public TicketMachine(int ticketCost)
{
price = ticketCost;
balance = 0;
total = 0;
}

public void insertMoney(int amount)
{
if(amount > 0)
balance += amount;
else
System.out.println("Use a positive amount: " + amount);
}

public void printTicket()
{
if(balance >= price) {
System.out.println("# The BlueJ Line");
System.out.println("# Ticket");
System.out.println("# " + price + " cents.");

total += price;
balance -= price;
}
else {
System.out.println("You must insert at least: " +
(price - balance) + " more cents.");
}
}

public int refundBalance()
{
int amountToRefund;

amountToRefund = balance;
balance = 0;
return amountToRefund;
}
}

a) int car [] = { 12, 14, -4, -3, 20, 8 };

b) TicketMachine [] busTerminal = { new TicketMachine(40),
new TicketMachine(30),
new TicketMachine(50)
};

c) char [] direction = new char[4];
direction[0]=’N’;
direction[1]=’E’;
direction[2]=’S’;
direction[3]=’W’;

d) HashMap <String, TicketMachine> busLine = new HashMap <String, TicketMachine> ();
busLine.put(“blue”, new TicketMachine(40));
busLine.put(“yellow”, new TicketMachine(30));
busLine.put(“red”, new TicketMachine(50));

e) ArrayList <String> notes = new ArrayList <String> ();
notes.add(“race”);
notes.add(“shop”);
notes.add(“study”);