#include <iostream>
#include <cstring>
using namespace std;


void *Memory_Copy(void *to,const void *from,size_t length)//把b拷貝到a 拷貝sizeof(b)個
{
    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));              //輸出 Today is the third of September
    printf("%s\n",a);
    Memory_Copy(a,c,sizeof(c));         //輸出 abcde is the third of September
    printf("%s\n",a);
    Memory_Copy(d,e,sizeof(e));
    cout
 
<<d[0]<<d[1]<<d[2]<<endl;       //輸出 983
    Memory_Copy(d,c,sizeof(c));
    cout<<d[0]<<" "<<d[1]<<" "<<d[2]<<endl;
    //輸出 1684234849 101 3  因為位元組序是小端，d[0]存放d c b a 的ascii碼 01100100 01100011 01100010 01100001
    //d[1]存放e的ascii碼且覆蓋了0000 1000   d[2]沒變化
    return 0;
}