这个us namespace std开头就是为了防止名字冲突,有四个循环第一个定义一个数组然后定义数组数的大小，然后里面各种赋值左移右移然后循环判定，比如学校人员统计系统。(The US namespace STD begins with force, and prevents the name from suddenly occurring. There are four cycles, which define the size of an array and array. Then the