下面程序段运行时输出结果是a=2,b=8 void main() { int x=1,y=1,a=2,b=7; switch(x) { case 1: switch(y) { case 0: a++;break; case 1: b++;break; } case 2: a++;b++;break; case 3: a++;b++; } printf("a=%d,b=%d\n",a,b); }