package 数据类型;
//作用域
class Scope {
public static void main(String args[]){
int x;
x = 10;
if(x == 10){
int y = 20;
System.out.println("x and y: " + x + " " + y);
x = y * 2;
}
// y = 100;//Error! y not known here
// x is still known here.
System.out.println("x is " + x);
}
}