Unit 1
int result = (int) (Math.random() * 10) + 1
What does this generate?
Generates an integer between 1 and 10, inclusive, and assigns it to the variable result.
boolean a = true;
boolean b = false;
boolean result = (a != b);
What will the value of result be?
true
What is required to create objects of a class?
Instance Variables
Constructors
Constructor Call from the Main Method
String[] animals = new String[5];
What is the code required to replace the animal at the last index of this array with "flamingo"?
animals[4] = "flamingo";
What rule MUST we follow when declaring the instance variables of a Java class?
int num = (int)(Math.random() * 6);
What value can num NEVER be?
6
(3 + 4 == 5) != (3 + 4 >= 5)
What value, if any, does the expression evaluate to?
true
What are the 4 different types of methods we can find in a Java class?
Void
Non Void
Accessor/Getter
Mutator/Setter
int[][] table = {{9, 8, 7}, {6, 5, 4}, {3, 2, 1}}; System.out.println(table[2][1]);
What value is printed as a result of executing the code segment?
2
Will you earn a penalty on the AP exam if you forget to type in the following symbols?
{ } ;
No, so long as the reader can easily understand the order/sequence of your code.
public Person(int idNumber, int age, boolean isActive) { /* implementation not shown */ }
Person p3 = new Person(3544, false, 18);
Why will this object instantiation NOT work?
The list of arguments given is not in the correct order by type. The second argument should be an int and the third argument should be a boolean.
boolean a = true; boolean b = true;
System.out.print((b || (!a || b)) + " ");
System.out.print(((!b || !a) && a) + " ");
System.out.println(!(a && b) && b);
What output is produced when this code segment is executed?
true false false
Explain, what is the purpose of a toString() method?
It returns a string that describes the attributes of an object you are referencing.
There is an ArrayList of Integer elements that represents the ages of all the students in the school. What code is required to determine how many elements are in this ArrayList?
.size() to identify the total number of elements
Convert this traditional for loop into an enhanced for loop. Assume names is an array of Strings.
for(int i = 0; i<names.length; i ++{
System.out.println(i);
}
for(String i : names){
System.out.println(i);
}
String str = "CompSci";
System.out.print(str.substring(1,4));
What will be printed?
omp
int count = 5;
while (count < 100) {
count = count * 2; }
count = count + 1;
What is the value of count after executing the code segment?
161
Explain, what is the purpose of the this keyword?
Programmers can give the parameter variables the same names as the instance variables and this can distinguish them and avoid a naming conflict.
Explain, what is recursion? What must happen in order for this process to STOP?
Recursion is when a method calls itself. It is a form of repetition.
In order to stop a recursive call, the base case must be met. The base case is the smallest possible problem (or problems) that the method knows how to solve, the ones it can answer directly without any more recursion.
Convert this for loop into a while loop:
for (int c = 1; c < 4; c++){
System.out.println(c);
}
int c = 1;
while(c < 4){
System.out.println(c);
c++;
}
String str = "Summer Break";
System.out.print(str.substring(7,8)+str.substring(1,6));
What will be printed?
Bummer
int n = 35;
int result = 1;
while (n > 0){
int d = n % 10;
result *= d;
n /= 10; }
System.out.println(result);
What is the output after the code has been executed?
15
A Java class can have many different constructors. Explain, what would be the purpose of having more than one constructor? What do we call this process in Java?
Sometimes you will want to write more than one constructor so that there are different ways of making an instance of your class. One reason to do that is to make it convenient to create instances from different kinds of arguments. This is called overloading.
What is required to traverse the elements in a 2D array? Explain why this is required.
A nested for loop is required.
The outer loop accesses the elements in the rows, the inner loop accesses the elements in each column.
Where did Ms. Morales go to school for undergrad and what did she major in?
Pepperdine University, Biology B.A