自定义字符串定长拼接函数my_strncat()

char *my_strncat(char*dest,constchar *ptr,intn)

{

    char *temp = dest;

    while(*temp != '\0')

    {

        temp++;

    }

    int i = 0;

    while(*ptr != '\0')

    {

        if(i == n)

        {

            break;

        }

        i++;

        *temp = *ptr;

        temp++;

        ptr++;

    }

    *temp = '\0';

    return dest;

}