Primitives

  • String Literals vs Literals, Exceptions,
  • OOP, compiles into javac first and into byte than runs on JVM

  • Garbage Collection, Multithreading - multiple programs at once

  • primitives - predefined, cannot call methods: Boolean, Int(2-3bits), Double(64bits), Char, Float, Long

  • Naming conventions

  • lowercase at start, words after is capital ( toTheMoon )

  • Casting

  • Manual casting vs automatic

  • Narrowing bigger -> smaller, Widening smaller -> bigger

  • Operator precedents

  • Left -> Right, PEMDAS

  • int x= 23;

  • x *= 2;
  • x %= 10;

  • System.out.println(x);

  • Scanners

  • import java.util.Scaner;
  • Scanner scan = Scanner(System.in);

Exercise/Game

Order : 1 -> 3 -> 2 -> 4 -> 6 -> 5

Homework

  • 2006 FRQ from College Board - Question 1, 2a and 3a

FRQ 1a-1c 

public class Appointment
{
 // returns the time interval of this Appointment
 public TimeInterval getTime()
 { /* implementation not shown */ }
 // returns true if the time interval of this Appointment
 // overlaps with the time interval of other;
 // otherwise, returns false
 public boolean conflictsWith(Appointment other){
    if(getTime().overlapsWith(other.getTime())){
        return true
    }
    else{
        return false
    }
 }
 // There may be fields, constructors, and methods that are not shown.
}

public class DailySchedule
{
 // contains Appointment objects, no two Appointments overlap
 private ArrayList apptList;
 public DailySchedule()
 { apptList = new ArrayList(); }
 // removes all appointments that overlap the given Appointment
 // postcondition: all appointments that have a time conflict with
 // appt have been removed from this DailySchedule
 public void clearConflicts(Appointment appt){
    int i = 0;
    while (i < apptList.size()){
        if (appt.conflictsWith((Appointment)(apptList.get(i)))){
            apptList.remove(i);
        }
        else{
            i++;
        }
    }
 } 
/* to be implemented in part (b) */ }
 // if emergency is true, clears any overlapping appointments and adds
 // appt to this DailySchedule; otherwise, if there are no conflicting
 // appointments, adds appt to this DailySchedule;
 // returns true if the appointment was added;
 // otherwise, returns false
 public boolean addAppt(Appointment appt, boolean emergency){
    if (emergency){
        clearConflicts(appt);
    }
    else{
        for (int i = 0; i < apptList.size(); i++){
            if (appt.conflictsWith((Appointment)apptList.get(i))){
                return false;
            }
        }
    }
    return apptList.add(appt); 
}

FRQ 2a 

public double purchasePrice()
{
 return (1 + taxRate) * getListPrice();
}

FRQ 3a 

public int compareCustomer(Customer other){
 int nameCompare = getName().compareTo(other.getName());
 if (nameCompare != 0){
    return nameCompare;
 }
 else{
    return getID() - other.getID();
 }
}