C++SOCKET多线程网络编程实现多个客户端与服务器通信

设计思路

程序设计分服务器端与客户端，其中，服务器端采用多线程，对于每个客户端连接时，均新建一个服务线程，之后判断客户端发来的信息是不是一个数学算式，是的话就返回计算结果给客户端。
客户端同样采用多线程，主线程是获取用户的输入，将输入发给服务器端。另一个线程则是监听服务器返回的结果，如果有返回就把结果打印到屏幕上。

代码

服务器端.

#include "pch.h"
#include 
#include 
#include
#include

#pragma comment(lib,"ws2_32.lib")
using namespace std;
const int PORT = 8000;
#define MaxClient 10
#define MaxBufSize 1024
#define _CRT_SECURE_NO_WARINGS

bool MathCalculate(char recvBuff[], char &resBuff);

//服务线程
DWORD WINAPI ServerThread(LPVOID lpParameter) {
	SOCKET *ClientSocket = (SOCKET*)lpParameter;
	int receByt = 0;
	char RecvBuf[MaxBufSize];
	char SendBuf[MaxBufSize];

	while (1) {
		receByt = recv(*ClientSocket, RecvBuf, sizeof(RecvBuf), 0);
		//buf[receByt]='\0';
		if (receByt > 0) {
			cout << "接收到的消息是：" << RecvBuf << "            来自客户端:" << *ClientSocket << endl;
			char ResBuf[MaxBufSize];
			if (MathCalculate(RecvBuf, *SendBuf)) {
				int k = 0;
				k = send(*ClientSocket, SendBuf, sizeof(SendBuf), 0);
				if (k < 0) {
					cout << "发送失败" << endl;
				}
				memset(SendBuf, 0, sizeof(SendBuf));
			}
		}
		else
		{
			cout << "客户端:" << *ClientSocket<< "接收消息结束！" << endl;
			break;
		}
		memset(RecvBuf, 0, sizeof(RecvBuf));
	}//while
	closesocket(*ClientSocket);
	free(ClientSocket);
	return 0;
}

int main() {
	WSAData wsd;
	WSAStartup(MAKEWORD(2, 2), &wsd);
	SOCKET ListenSocket = socket(AF_INET, SOCK_STREAM, 0);
	SOCKADDR_IN ListenAddr;
	ListenAddr.sin_family = AF_INET;
	ListenAddr.sin_addr.S_un.S_addr = INADDR_ANY;//表示填入本机ip
	ListenAddr.sin_port = htons(PORT);
	int n;
	n = bind(ListenSocket, (LPSOCKADDR)&ListenAddr, sizeof(ListenAddr));
	if (n == SOCKET_ERROR) {
		cout << "端口绑定失败！" << endl;
		return -1;
	}
	else {
		cout << "端口绑定成功：" << PORT << endl;
	}
	int l = listen(ListenSocket, 20);
	cout << "服务端准备就绪，等待连接请求" << endl;

	while (1) {
		//循环接收客户端连接请求并创建服务线程
		SOCKET *ClientSocket = new SOCKET;
		ClientSocket = (SOCKET*)malloc(sizeof(SOCKET));
		//接收客户端连接请求
		int SockAddrlen = sizeof(sockaddr);
		*ClientSocket = accept(ListenSocket, 0, 0);
		cout << "一个客户端已连接到服务器，socket是：" << *ClientSocket << endl;
		CreateThread(NULL, 0, &ServerThread, ClientSocket, 0, NULL);
	}//while
	closesocket(ListenSocket);
	WSACleanup();
	return(0);
}//main


char startBuf[5] = { "MATH" };
bool MathCalculate(char recvBuff[],char &resBuff) {
	bool getTrue = false;
	for (int i = 0; i < 4; i++) {
		if (recvBuff[i] == startBuf[i]) {
			getTrue = true;
			continue;
		}
		else {
			getTrue = false;
			break;
		}
	}
	int equalIndex = 0;
	int mathflag = 0;
	int mathflagIndex = 0;
	if (getTrue) {
		getTrue = false;
		for (int i = 0; i < 50; i++) {
			if (recvBuff[i] == '=') {
				getTrue = true;
				equalIndex = i;
				break;
			}
		}
	}
	if (getTrue) {
		getTrue = false;
		for (int i = 0; i < equalIndex; i++) {
			switch (recvBuff[i]) {
			case '+':
				getTrue = true;
				mathflag = 1;
				mathflagIndex = i;
				break;
			case '-':
				getTrue = true;
				mathflag = 2;
				mathflagIndex = i;
				break;
			case '*':
				getTrue = true;
				mathflag = 3;
				mathflagIndex = i;
				break;
			case '\\':
			case '/':
				getTrue = true;
				mathflag = 4;
				mathflagIndex = i;
				break;
			}
			if (getTrue) {
				break;
			}
		}
		if (getTrue) {
			int a = 0, b = 0;
			for (int i = 4; i < mathflagIndex; i++) {
				a = a * 10 + recvBuff[i] - '0';
			}
			for (int i = mathflagIndex + 1; i < equalIndex; i++) {
				b = b * 10 + recvBuff[i] - '0';
			}

			switch (mathflag) {
			case 1:
				printf("%d+%d=%d\n", a, b, a + b);
				sprintf(&resBuff, "Result:%d+%d=%d\n", a, b, a + b);
				break;
			case 2:
				printf("%d-%d=%d\n", a, b, a - b);
				sprintf(&resBuff, "Result:%d-%d=%d\n", a, b, a - b);
				break;
			case 3:
				printf("%d*%d=%d\n", a, b, a * b);
				sprintf(&resBuff, "Result:%d*%d=%d\n", a, b, a * b);
				break;
			case 4:
				printf("%d//%d=%d\n", a, b, a / b);
				sprintf(&resBuff, "Result:%d//%d=%d\n", a, b, a / b);
				break;
			default :
				printf("No Result");
				sprintf(&resBuff, "No Result");
				break;
			}
		}
	}
	return getTrue;
}

客户端

#include "pch.h"
#include 
#include 
#include
#include

#pragma comment(lib,"ws2_32.lib")
using namespace std;
const int PORT = 8000;
#define MaxBufSize 1024
#define _CRT_SECURE_NO_WARINGS


//监听来自服务器的消息
DWORD WINAPI  recvFromServer(LPVOID lpParameter)
{
	char buf[MaxBufSize];
	SOCKET *ClientSocket = (SOCKET*)lpParameter;
	while (1) {
		memset(buf, '\0', sizeof(buf));
		if (recv(*ClientSocket, buf, 1024, 0) <= 0)
		{
			printf("关闭连接!\n");
			break;
			closesocket(*ClientSocket);
		}
		std::cout << buf << "\n";
	}
	return 0;
}


int main() {
	WSADATA wsd;
	WSAStartup(MAKEWORD(2, 2), &wsd);
	SOCKET SocketClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	SOCKADDR_IN  ClientAddr;

	ClientAddr.sin_family = AF_INET;
	ClientAddr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	ClientAddr.sin_port = htons(PORT);
	int n = 0;
	n = connect(SocketClient, (struct sockaddr*)&ClientAddr, sizeof(ClientAddr));
	if (n == SOCKET_ERROR) {
		cout << "连接失败" << endl;
		return -1;
	}
	cout << "已经连接到服务器，可以向服务器发送消息了！" << endl;
	CreateThread(NULL, 0, &recvFromServer, &SocketClient, 0, NULL);
	char info[1024], SendBuff[MaxBufSize], RecvBuff[MaxBufSize];
	while (1) {
		cout << "请输入要发送的信息,按回车结束发送：" << endl;
		cin>>info;
		if (info[0] == '\0')
			break;

		sprintf(SendBuff, "MATH");
		strcat(SendBuff, info);
		memset(info, 0, sizeof(info));
		int k = 0;
		n = send(SocketClient, SendBuff, sizeof(SendBuff), 0);
		memset(SendBuff, 0, sizeof(SendBuff));
		if (k < 0) {
			cout << "发送失败" << endl;
		}
		Sleep(500);
		memset(RecvBuff, 0, sizeof(RecvBuff));
	}
	closesocket(SocketClient);
	WSACleanup();
	return 0;
}

展示

说明：三个框中，左边的是服务器，中间的和右边的是两个客户端。