自定義字符串定長拷貝函數my_strncpy()

char * my_strncpy(char *dest,const char *ptr,int n)

{

    char *temp = dest;

    int i = 0;

    while(*ptr != '\0')

    {

        if(i == n)

        {

            break;

        }

        i++;

        *temp = *ptr;

        temp++;

        ptr++;

    }

    *temp = '\0';

    return dest;

}