已知:class Employee;class Manager extends Employee;class Director extends Employee;则以下语句能通过编译的有哪些?
A. Employee e = new Manager();
B. Director d = new Manager();
C. Director d = new Employee();
D. Manager m = new Director()
要产生【20,999】之间的随机整数可以使用以下哪个表达式?
A. (int )(20+Math.random()*97)
B. 20+(int)(Math.randow() * 980)
C. (int)Math.random() * 999
D. 20 + (int)Math.random() * 980
下面哪一个是窗口正在关闭事件处理方法()
A. windowClosing
B. windowClosed
C. windowDeactivated
D. windowDeiconified
byte类型变量在内存中的位数为
A. 8
B. 16
C. 32
D. 64