新手求教，c++调用类是不是只要#include(类名)就可以了，小弟我这样调用提示说打不开那个类（是另外下载的）

新手求教，c++调用类是不是只要#include(类名)就可以了，我这样调用提示说打不开那个类（是另外下载的）
还有在编译的时候提示这样的信息。应该怎么修改：
D:\tools\Microsoft   Visual   Studio\MyProjects\tongxun\tongxun.cpp(15)   :   error   C2065:   'outportb '   :   undeclared   identifier
D:\tools\Microsoft   Visual   Studio\MyProjects\tongxun\tongxun.cpp(27)   :   error   C2065:   'inportb '   :   undeclared   identifier
D:\tools\Microsoft   Visual   Studio\MyProjects\tongxun\tongxun.cpp(114)   :   error   C2065:   'sendch '   :   undeclared   identifier
D:\tools\Microsoft   Visual   Studio\MyProjects\tongxun\tongxun.cpp(115)   :   error   C2065:   'recievefile '   :   undeclared   identifier

下面是源程序
#include   <sys\stat.h>
#include   <string.h>
#include   <fcntl.h>
#include   <io.h>
#include   <stdio.h>
#include   <stdlib.h>
#include   <dos.h>
#include   <CONIO.H>
#define   COM1   0x2f8
#define   COM2   0x2f8
void   SendCh()   {
unsigned   char   status;
int   i,c;
int   flag=1;
outportb(COM1+1,0x00);
outportb(COM1+1,0x40);
outportb(COM1+1,0xcf);
outportb(COM1+1,0x37);

printf( "Input   a   character: ");
while(flag)   {
c=getch();
putchar(c);
if   (c==27)   flag=0;
for   (i=0;i <=1000;i++);
do   {
status=inportb(0x2f9);
status=status   &   0x01;
}while   (status==0);
outportb(COM1,c);
}
printf( "complete\n ");
}
 
void   goon()
{
printf( "Press   any   key   to   continue...\n ");
while   (!kbhit())   ;
getch();
}
void   ReceiveCh()   {
int   i;
char   ch=0;
unsigned   char   status;
outportb(COM2+1,0xAA);
outportb(COM2+1,0x50);
outportb(COM2+1,0xcf);
outportb(COM2+1,0x14);
printf( "Receiving   ...\n ");
while(ch!=27)   {
for   (i=0;i <=1000;i++);
do   {
status=inportb(COM2+5);
status=status   &   0x01;
}while   (status==0);
ch=inportb(COM2);
printf( "%c ",ch);
}
}
void   Receivefile()   {
FILE   *fp;
int   handle;
int   flag=1;
char   c;
int   i;
unsigned   char   status;
char   fname[]= "receive.txt ";
outportb(COM2+1,0xAA);
outportb(COM2+1,0x50);
outportb(COM2+1,0xcf);
outportb(COM2+1,0x14);

handle=creat(fname,   S_IREAD|S_IWRITE);
if(handle==-1)   {
printf( "Creat   file   Faild.\n ");
exit(0);
}
if((fp=fopen(fname, "w "))==NULL)   {
printf( "Open   file   Faild.\n ");
exit(0);
}
printf( "Receiving   file(rename:receive.txt)...\n\n ");
while(flag)   {
do   {
status=inportb(COM2+5);
status=status   &   0x01;
}while   (status==0);
c=inportb(COM2);
for   (i=0;i <=1000;i++);
if(c==27)   {
fclose(fp);
flag=0;
printf( "%c ",c);
break;
}
printf( "%c ",c);
fputc(c,fp);
}
close(handle);
printf( "\n\n   ok   \n ");
}
void   main(){
char   ch=0;