C++实现内存复制函数（memmove解决内存重叠）

void* my_memmove(void*dest, const void* src, size_t n)
{
char*_dest = (char*)dest;
const char*_src = (char*)src;
if (_dest > _src&&_dest < _src + n)//发生区域重叠
{
while (n--)
{
*_dest--= *(_src+n);//逆向复制
}
}
else//未发生区域重叠 正向复制
{
while (n--)
{
*_dest++ = *_src++;
}
}
return dest;
}
int main()
{
int s[4] = {1,2,3,4};
for (int i = 0; i < 4; i++)
{
cout << s[i] << "";
}
cout << endl;
my_memmove(s+2, s + 3,1*sizeof(int));
for (int i = 0; i < 4; i++)
{
cout << s[i]<<"";
}
getchar();
return 0;
}