关于c++const与指针的问题

比如
const int *p;
int const *p;
const int const *p;
int *const p;


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const size_t arr_size = 5;
          int arr[arr_size] = {1,2,3,4,5};
          int *p = arr;         
          int *p2 = p + arr_size;
int *p = arr;   与int *p = &arr;  
有什么区别