C语言 实现一个内存拷贝函数

#include<stdio.h>

void *Memory_Copy(void *to,const void *from,size_t length)//把b拷贝到a 拷贝sizeof(b)个
{
    char *from_p=(char *)from;
    char *to_p=(char *)to;

    if(from_p > to_p) {
        for(int i = 0;i < length; i++)
        {
            *to_p++=*from_p++;
        }
    }
    else{
        from_p += length-1;
        to_p += length-1;
        for (int i = 0; i < length; i++)
        {
            *to_p--=*from_p--;
        }
    }
    return to_p;
}
int main()
{
    char a[64];
    char b[]="Today is the third of September";
    char c[]={'a','b','c','d','e'};
    int d[]={1,2,3};
    int e[]={9,8};
    memcpy(a,b,sizeof(b));              //输出 Today is the third of September
    printf("%s\n",a);
    Memory_Copy(a,c,sizeof(c));         //输出 abcde is the third of September
    printf("%s\n",a);
    Memory_Copy(d,e,sizeof(e));
    cout<<d[0]<<d[1]<<d[2]<<endl;       //输出 983
    Memory_Copy(d,c,sizeof(c));
    cout<<d[0]<<" "<<d[1]<<" "<<d[2]<<endl;
    //输出 1684234849 101 3  因为字节序是小端，d[0]存放d c b a 的ascii码 01100100 01100011 01100010 01100001
    //d[1]存放e的ascii码且覆盖了0000 1000   d[2]没变化
    return 0;
}