int x = ;

    goto JUMP;

    printf("x is : %d\n",x);

JUMP:

    int a = ;  <=== 错误，lable后面不能申明变量，只能是表达式语句(statement)，哪怕是空语句..

    printf("%d",a);

    int x = ;

    goto JUMP;

    printf("x is : %d\n",x);

JUMP: ;     /// 空语句，正确

    int a = ;     // 前面有空语句，正确

    printf("%d",a);