memcpy函数的实现.
//把src指向的对象中的num个字符拷贝到dest所指向的对象中,返回指向结果对象的指针.
void *memcpy(void *dest, void *src, size_t num)
{
char *pd = (char *)dest;
char *ps = (char *)src;
while (num-- && *ps != '\0')
*pd++ = *ps++ ;
return dest;
}
//实strcpy函数现
char *strcpy(char *des,char *src)
{
if(src == NULL)
return NULL;
char *address = des;
while((*des++ = *src++) != '\0');
return address;
}