Windows下的TCP和UDP网络编程

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一.面向连接–TCP

特性

传输过程中数据不会丢失
按照顺序传输数据
不存在数据边界

流程：

服务端代码

#include<winsock2.h>
#include<stdlib.h>
#include<stdio.h>
#pragma comment(lib,"ws2_32.lib")
int main() {
   

	printf("TCP Server\n");
	//初始化网络库

// 加载套接字库
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;
	wVersionRequested = MAKEWORD(1, 1);
	// 初始化套接字库
	err = WSAStartup(wVersionRequested, &wsaData);
	if (err != 0)
	{
   
		return err;
	}
	if (LOBYTE(wsaData.wVersion) != 1 || HIBYTE(wsaData.wVersion) != 1)
	{
   
		WSACleanup();
		return -1;
	}
	//创建套接字
	SOCKET sockSrv = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
	if (sockSrv == INVALID_SOCKET) {
   
		printf("create socket error: %s\n",GetLastError());
		return -1;
	}
	SOCKADDR_IN addrSrv;
	addrSrv.sin_addr.S_un.S_addr = htons(INADDR_ANY);
	addrSrv.sin_family = AF_INET;
	addrSrv.sin_port = htons(6000);
	//bind
	if (SOCKET_ERROR == bind(sockSrv, (SOCKADDR*)&addrSrv, sizeof(addrSrv)))
	{
   
		printf("bind error = %d\n", GetLastError());
	}
	//listen
	if (SOCKET_ERROR == listen(sockSrv, 5))// 最大监听数目，执行到listen,未执行到accept//该部可以接受连接放到队列，
		//但是不会处理数据
	{
   
		printf("listen error = %d\n", GetLastError());
	}
	printf("sleep start");
	Sleep(60000);
	printf("slepep end");
	SOCKADDR_IN addrCil;
	int len = sizeof(addrCil);
	while (TRUE) {
   
		SOCKET sockConn= accept(sockSrv, (SOCKADDR*)&addrCil, &len);
		char sendBuf[100] = {
    0 };
		sprintf_s