遇到问题：用另一个指针除指针的sizeof值

#include "mp.h"
    void maopao(int mp[])
    {
        int  a = (sizeof(mp) / sizeof(mp[0]));
        cout << "冒泡前的数列" << endl;
        for (int num0 = 0; num0 < a; num0++)
        {
            cout << mp[num0] << " ";
        }
        cout << endl;
        for (int j = 0; j < a - 1; j++)
        {
            for (int i = 0; i < a - j - 1; i++)
            {
                if (mp[i] > mp[i + 1])
                {
                    int temp = mp[i];
                    mp[i] = mp[i + 1];
                    mp[i + 1] = temp;
                }
            }
        }
        cout << "冒泡后的数列：" << endl;
        for (int num = 0; num < a; num++)
        {
            cout << mp[num] << " ";
        }
        cout << endl;
    }