1. What is the purpose of each of the following mechanisms for a program to communicate with its environment?

1. A. a mechanism for the program to display output information other than data, such as error or debug messages
2. B. provide information, such as settings or options, to control the program's behavior without having to change the program's code
3. C. the default mechanism for the program to read input data
4. D. the default mechanism for the program to write output data

select	1. command-line argument
select	2. standard input
select	3. standard output
select	4. standard error

2. Which is a simple yet effective way to implement a Comparator that represents ascending order of two Integer arguments x and y?

• A. x +y
• B. x - y
• C. x / y
• D. y - x