客户端与服务器端的通讯，C++书写步骤。

要实现客户端与服务器端的通讯，需要两部分C++的程序：服务器端程序代码和客户端代码。

首先是服务器端程序代码：

#include <WinSock2.h>

#include <stdio.h>

#include <stdlib.h> 

#pragma comment(lib, "ws2_32.lib")

void main()

{

WSADATA wsaData

int port = 5099

char buf[] = "Server: hello, I am a server....."

if(WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)

{

printf("Failed to load Winsock")

return

} 

//创建用于监听的套接字

SOCKET sockSrv = socket(AF_INET, SOCK_STREAM, 0)

SOCKADDR_IN addrSrv

addrSrv.sin_family = AF_INET

addrSrv.sin_port = htons(port)//1024以上的端口号

addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY)

int retVal = bind(sockSrv, (LPSOCKADDR)&addrSrv, sizeof(SOCKADDR_IN))

if(retVal == SOCKET_ERROR){

printf("Failed bind:%d\n", WSAGetLastError())

return

}

if(listen(sockSrv,10) ==SOCKET_ERROR){

printf("Listen failed:%d", WSAGetLastError())

return

}

SOCKADDR_IN addrClient

int len = sizeof(SOCKADDR)

while(1)

{

//等待客户请求到来

SOCKET sockConn = accept(sockSrv, (SOCKADDR *) &addrClient, &len)

if(sockConn == SOCKET_ERROR){

printf("Accept failed:%d", WSAGetLastError())

break

}

printf("Accept client IP:[%s]\n", inet_ntoa(addrClient.sin_addr))

//发送数据

int iSend = send(sockConn, buf, sizeof(buf) , 0)

if(iSend == SOCKET_ERROR){

printf("send failed")

break

}

char recvBuf[100]

memset(recvBuf, 0, sizeof(recvBuf))

//      //接收数据

recv(sockConn, recvBuf, sizeof(recvBuf), 0)

printf("%s\n", recvBuf)

closesocket(sockConn)

}

closesocket(sockSrv)

WSACleanup()

system("pause")

}

接下来是客户端代码：

#include <WinSock2.h> 

#include <stdio.h>

#pragma comment(lib, "ws2_32.lib")

void main()

{

//加载套接字

WSADATA wsaData

char buff[1024]

memset(buff, 0, sizeof(buff))

if(WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)

{

printf("Failed to load Winsock")

return

}

SOCKADDR_IN addrSrv

addrSrv.sin_family = AF_INET

addrSrv.sin_port = htons(5099)

addrSrv.sin_addr.S_un.S_addr = inet_addr("127.0.0.1")

//创建套接字

SOCKET sockClient = socket(AF_INET, SOCK_STREAM, 0)

if(SOCKET_ERROR == sockClient){

printf("Socket() error:%d", WSAGetLastError())

return

}

//向服务器发出连接请求

if(connect(sockClient, (struct  sockaddr*)&addrSrv, sizeof(addrSrv)) == INVALID_SOCKET){

printf("Connect failed:%d", WSAGetLastError())

return

}else

{

//接收数据

recv(sockClient, buff, sizeof(buff), 0)

printf("%s\n", buff)

}

//发送数据

char buff = "hello, this is a Client...."

send(sockClient, buff, sizeof(buff), 0)

//关闭套接字

closesocket(sockClient)

WSACleanup()

}

一个server端

Private Sub Command1_Click()

End

End Sub

Private Sub Command2_Click()

Winsockserver.SendData Text4.Text + ":" + textsend.Text

textget.Text = textget.Text + vbCrLf + Text4.Text + ":" + textsend.Text + " " + Str(Time)

textsend.Text = ""

End Sub

Private Sub Form_Load()

Command2.Visible = False

textsend.Visible = False

Text4.Visible = False

textget.Visible = False

Label1.Visible = False

Winsockserver.LocalPort = 1001

Winsockserver.Listen

End Sub

Private Sub textsend_Change()

'Winsockserver.SendData textsend.text

End Sub

Private Sub textsend_KeyPress(KeyAscii As Integer)

'If KeyAscii = 13 Then

'Winsockserver.SendData textsend.text

'textsend.text = ""

If KeyAscii = 13 Then

Winsockserver.SendData textsend.Text

' Text1.text = Text1.text + vbCrLf + Text4.text + ": " + Text2.text + " " + Str(Time)

textsend.Text = ""

End If

End Sub

Private Sub Timer1_Timer()

If Text4.Text = "" Then Text4.Text = "no name"

End Sub

Private Sub Winsockserver_Close()

Winsockserver.Close

End

End Sub

Private Sub Winsockserver_ConnectionRequest(ByVal requestID As Long)

Command2.Visible = True

textsend.Visible = True

textget.Visible = True

Text4.Visible = True

Label1.Visible = True

If Winsockserver.State <>sckClosed Then Winsockserver.Close

Winsockserver.Accept requestID

End Sub

Private Sub Winsockserver_DataArrival(ByVal bytesTotal As Long)

Dim tmpstr As String

Winsockserver.GetData tmpstr

'textget.text = textget + tmpstr + textsend

textget.Text = textget.Text + vbCrLf + tmpstr + " " + Str(Time)

End Sub

'（1）Command1：退出按钮；

'（2）textsend：发送数据文本框；

'（3）Winsockserver： 服务器Winsock；

'（4）textget ：接收数据文本框。

一个clien

rho_b1=0:5:35

rho_b2=0:0.1:35

for i=1:length(rho_b1)

smlid_err_prb(i)=ssfh_Pe(rho_b1(i))

end

for i=1:length(rho_b2)

temp=10^(rho_b2(i)/10)

if(temp>2)

theo_err_rate(i)=1/(exp(1)*temp)

else

theo_err_rate(i)=(1/2)*exp(-temp/2)

end

end

semilogy(rho_b1,smlid_err_prb,'k*',rho_b2,theo_err_rate,'k-)

在程序中调用了ssfh_Pe子函数，程序如下：

function[p]=ssfh_Pe(tho_in_dB)

rho=10^(rho_in_dB/10)

Eb=rho

if(rho>2) alpa=2/rho

else alpa=1

end

agma=sqrt(1/(2*alpha))

N=10000

for i=1:N

temp=rand

if(temp<0.5)data(i)=1

else data(i)=0

end

end

for i=1:N

if(data(i)==0)

rlc(i)=sqrt(Eb)rls(i)=0r2c(i)=0r2s(i)=0

else

rlc(i)=0rls(i)=0r2c(i)=sqrt(Eb)r2s(i)=0

end

if(rand<alpha)

rlc(i)=rlc(i)+gngauss(sgma)

rls(i)=rls(i)+gngauss(sgma)

r2c(i)=r2c(i)+gngauss(sgma)

r2s(i)=r2s(i)+gngauss(sgma)

end

end

num_of_err=0

for i=1:N

r1=rlc(i)^2+rls(i)^2

r2=r2c(i)^2+r2s(i)^2

if(r1>r2)decis=0

else decis=1

end

if(decis~=data(i))

num_off_eff=num_of_err+1

end

end

p=num_of_err/N

其中高斯分布随机变量函数gngauss程序如下

function[gsrv1,gsrv2]=gngauss(n,sgma)

if nargin==0,

m=0sgma=1

elseif nargin==1,

sgma=mm=0

end

u=rand

z=sgma*(sqrt(2*log(1/(1-u))))

u=rand

gsrv1=m+z*cos(2*pi*u)

gsrv2=m+z*sin(2*pi*u)

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