模拟实现memcpy，memmove

1。
模拟实现memcpy （内存拷贝）（拷贝字符串时不会自动加’\0’）
注：memcpy拷贝时没有考虑到内存交叉

#include <stdio.h>
#include <string.h>
#include <assert.h>

void *my_memcpy ( void *det ,const char *src ,size_t count)
{
    void *ret = det;
    assert(det);
    assert(src);
    while(count--)
    {
       *(char *)det = *(char*)src ;
       det = (char*)det + 1;
       src = (char*)src + 1;
    }
    return ret;
}
int main()
{
    char str[]="1234abc886";
    char arr[20];
    char *ps = NULL;
    char *pp = NULL; 
    ps = my_memcpy(arr,str,strlen(str)+1);
    pp = memcpy(arr,str,strlen(str)+1);
    printf("my_memcpy :%s\n",pp);
    printf("memcpy :%s\n",ps);
    return 0;
}

2。
模拟实现memmove （内存拷贝）

---

---

#include <stdio.h>
#include <string.h>
#include <assert.h>

void *my_memmove ( void *det ,const char *src ,size_t count)
{
    void *ret = det;
    assert(det);
    assert(src);

    if(det <= src || ((char*)det) >= ((char*)src + count))
    {
        while(count--)
        {
           *(char *)det = *(char*)src ;
           det = (char*)det + 1;
           src = (char*)src + 1;
        }
    }
    else
    {
           det = (char*)det + count - 1;
           src = (char*)src + count - 1;
        while(count--)
        {
           *(char *)det = *(char*)src ;
           det = (char*)det - 1;
           src = (char*)src - 1;
        }
    }
    return ret;
}

int main()
{
    char str[]="1234abc886";
    char arr[20] = " ";
    char *pp = NULL; 
    *arr = str + 4;
    pp = my_memmove(arr,str,7);
    printf("my_memmove :%s\n",pp);
    return 0;
}