++a a++的再次理解

public class Test {

//// public static void main(String[] args) throws InterruptedException {

// TODO Auto-generated method stub
 int a=1;
 
 int b=2;
 
 int c;
 
 int d;
 
 c=++b;
 d=a++;
 c++;
 System.out.println(a);
 System.out.println(b);
 System.out.println(c);
 System.out.println(d);
 
 int x=4;
 int y=5;
 y=x++;
 System.out.println(y);
}

}

输出：2 3 4 1 4