Below are some of the common mistakes I found on your AP Computer Science A homework and exams; please make sure you do not make the same mistakes:
Do not use the keyword new as a variable name
The backslash used in Escape Sequences looks like this: backslash ( \ ).
The casting operator such as (int), (double), etc must be placed in front of an expression, never in the back.
The charAt method from String class returns a char which is a primitive data; use the substring method instead.
To return a value from a method, the keyword is return. Do not print out the value. Printing out a value is not the same as returning a value.
The nth letter in a String or the nth element in an array is at index n - 1. Remember in Java, index starts from 0.
If you have any questions regarding this AP Computer Science A course, please send me and email (chenhuo@bxscience.edu) with title "AP CS A Q&A". I will post the answer here to share with everybody.
Frequently Asked Questions
Q: I missed an exam due to medical or other excusable reason, when can I take the makeup exam.
A: Your makeup exam will be automatically scheduled to the immediate upcoming SGI. You can also schedule a date with me before the immediate upcoming SGI.
Q: This is a computer programming class. Why do you sometime ask us to write down code on paper instead of just typing them on computer?
A: Good question. The answer is simple, because the AP Computer Science A exam is paper based so we need to prepare you for that!
Q: Why does statement System.out.println(0.2 + 0.2 + 0.2); print 0.6000000000000001 instead of 0.6?
A: When floating-point numbers are converted to binary, most cannot be represented exactly, leading to round-off error. These errors are compounded by arithmetic operations.
Q: Can we use super.super.something()?
A: No.
Q: What is the format of the AP Computer Science A exam?
A: As of November 2017: The AP Computer Science A exam consists of two sections.
Section I: Multiple Choice | 40 Questions | 1 Hour, 30 Minutes | 50% of Exam Score
Section II: Free Response | 4 Questions | 1 Hour, 30 Minutes | 50% of Exam Score
Q: What writing instrument should I use on the AP Computer Science A exam?
A: Pencil for Section I and Section II. (https://apcentral.collegeboard.org/media/pdf/ap-comp-sci-a-exam-instructions.pdf)
Q: Are calculators allowed on the AP Computer Science A exam?
A: No.
Q: I get above 85% on the most recent exam, does it mean that I will be dropped from the mandatory SGI program?
A: No. just because you get above 85% on the most recent exam does not mean you will be dropped from the mandatory SGI program. It depends on many factors. You will be notified if you are dropped from the mandatory SGI program. You cannot decide when you will be dropped from the mandatory SGI program. Please do not ask me repeatedly.