Class Counter gives each instance its own integer member variable count (0 when created), and its method inc() adds 1 to its own count. What is the value of x after the following program runs?

Answer: B. 31

In object-oriented programming, new Counter() creates a new instance each time, so c1 and c2 each have their own count. c1.inc() increments only c1's count, so c1.count = 3 and c2.count = 1. x = 3 × 10 + 1 = 31. Member variable values are kept separately for each instance.

• A. This mixes up the counts of c1 and c2.
• B. Correct. c1.count = 3 and c2.count = 1.
• C. This assumes count is shared by all instances. Each instance has its own member variables.