分析以下程序的运行结果,并上机运行验证。 int x = 10; int a = x + x++; System.out.println("a =" + a); System.out.println("x =" + x); int b = x + ++x; System.out.println("b =" + b); System.out.println("x =" + x); int c = x + x--; System.out.println("c =" + c); System.out.println("x =" + x); int d = x + --x; System.out.println("d =" + d); System.out.println("x =" + x);