strcpy and strncpy

已知strcpy()的函数原型：char *strcpy(char *dest, const char *src)其中dest是目的字符串，src是源字符串。不调用C++/C的字符串库函数，请编写函数strcpy()。


char *strcpy(char *dest, const char *src)
{
    if (dest == NULL || src == NULL)
        return NULL;
    if (dest == src)
        return dest;

    char *tmp = dest;
    while(*src) {
        *dest = *src;
        dest++;
        src++;
    }
    *dest = '\0';
    dest = tmp;
    return dest;
}

char * strncpy(char * dest,const char *src,size_t count)

{

char *tmp = dest;

while (count) {

  if ((*tmp = *src) != 0) src++;

  tmp++;

  count--;

}

return dest;

}