Hex, Binary, and other Math Headaches
String Things
I Deserve Arrays
The Scariest Variables (Booooooleans)
3RR0R!
100
Convert 32 to binary
100000
100
String s = "hello";
System.out.println(s.charAt(0));
What will print?
h
100
To access the first element of an array use this command.
array[0]
100
What does this statement evaluate to?
!(true && false) || ((false || false) && true)
true
100
What type of error prevents the code from compiling?
Syntax Error
200
Convert 10011001 to decimal
153
200
How do we find out how long a String variable called word is?
word.length()
200
An array of length 7 would have positions for elements up to #_.
6
200
When will this statement evaluate to true?
!B && A
When A is true and B is false
200
What type of error prevents the code from running successfully?
Runtime Error
300
Convert 26 to hexadecimal
1A
300
If we wanted to separate only the first three characters from String word for some coding purpose, we could call:
word.substring(0,3);
300
To find out how many elements are contained in an array, we call
array.length
300
!(a <= b) && (a * b > 0)
This statement will always evaluate to true if what condition is also true?
A) a = b
B) a > b
C) a < b
D) a > b and b > 0
E) a > b and b < 0
a > b and b > 0
300
What type of error results in unexpected or incorrect output?
Logic Error
400
There are 10 types of people in the world. Those who understand binary and ???
those who don't.
400
Consider this code:
String x = "abcdefg";
int y = x.indexOf(d);
What is the value of y?
3
400
To access the last element of an array without knowing how many elements are in an array, we would call
array[array.length - 1]
400
If boolean variables A,B, and C are all true, what will this statment evaluate to?
!(!A && !B && !C)
true
400
What type of error is shown here:
String[] array = {"hi", "hey there", "hello"};
array[3] = "salutations";
Runtime Error
500
Convert 8D to binary
10001101
500
Consider this code:
String x = "hello";
String y = new String("hello");
boolean z = x == y;
What is the value of z?
false
500
To access the second to last element of an array without knowing how many elements are in an array, we would call
array[array.length - 2]
500
Create a truth table for the following statement:
(A && !B) || C
500
What type of error is shown below (Disregard any unintialized variables)?
int n = kb.nextInt();
while(n >= 0){
System.out.println("That's a nonnegative number!");
}
Logic Error