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一、TCP的服务器客户端编程流程
1、服务器 ser.c
1 #include <stdio.h>
2 #include <assert.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5 #include <string.h>
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9
10 int main()
11 {
12 int sockfd = socket(AF_INET, SOCK_STREAM, 0);//创建套接字
13 assert(sockfd != -1);
14
15 struct sockaddr_in saddr,caddr;//服务端，客户端
16 memset(&saddr, 0, sizeof(saddr));//清屏
17 saddr.sin_family = AF_INET;//协议
18 saddr.sin_port = htons(6000);//端口,1024 root 5000，主机转网络
19 saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
20
21 int res = bind(sockfd, (struct sockaddr*)&saddr, sizeof(saddr));//绑定
22 assert(res != -1);
23
24 listen(sockfd, 5);//创立监听队列
25 while(1)
26 {
27 int len = sizeof(caddr);
28 //c链接套接字 ,sockfd接听套接字
29 int c = accept(sockfd,(struct sockaddr*)&caddr,&len);
30 if(c < 0)
31 {
32 continue;
33 }
34 char buff[128] = {0};
35 recv(c, buff, 127, 0); //有可能阻塞,一次只能处理一个客户端
36 printf("buff=%s\n",buff);
37 send(c, "ok", 2, 0);
38 close(c);
39 }
40 }
2.客户端cli.c
socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9
10 int main()
11 {
12 int sockfd = (AF_INET, SOCK_STREAM, 0);
13 assert(sockfd != -1);
14
15 struct sockaddr_in saddr;
16 memset(&saddr, 0, sizeof(saddr));//清空saddr
17 saddr.sin_family = AF_INET;
18 saddr.sin_port = htons(6000);
19 saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
20
21 int res = connect(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));
22 assert(res != -1);
23
24 char buff[128] = {0};
25
26 printf("input:\n");
27 fgets(buff, 128, stdin);
28
29 send(sockfd, buff, strlen(buff), 0);
30 memset(buff, 0, 128);
31 recv(sockfd, buff, 127,0);
32 printf("buff=%s\n",buff);
33
34 close(sockfd);
35 }
二、TCP服务器客户端的循环实现
1、服务器端ser1.c
1 #include <string.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5 #include <assert.h>
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9
10 //服务器与客户端的循环实现
11 int main()
12 {
13 int sockfd = socket(AF_INET, SOCK_STREAM, 0);//套接字
14 assert(sockfd != -1);
15 struct sockaddr_in saddr, caddr;
16 memset(&saddr,0, sizeof(saddr));
17 saddr.sin_family = AF_INET;
18 saddr.sin_port = htons(6001);
19 saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
20
21 int res = bind(sockfd, (struct sockaddr*)&saddr, sizeof(saddr));
22 assert(res != -1);
23 listen(sockfd, 5);//转为被动监听套接字，5表示监听队列长度
24
25 while(1)
26 {
27 int len = sizeof(caddr);
28 int c = accept(sockfd, (struct sockaddr*)&caddr, &len);
29 if(c < 0)
30 {
31 continue;
32 }
33 printf("accept c=%d\n",c);
34
35 while(1)
36 {
37 char buff[128] = {0};
38 int n = recv(c, buff, 127, 0);//返回值为0，表示对方已关闭，开始进行四次挥手
39 if(n <= 0)
40 {
41 break;//若对方关闭连接，则退出小循环
42 }
43 printf("buff=%s\n", buff);
44 send(c, "ok", 2, 0);
45 }
46 close(c);
47 }
48 }
2、客户端cli.c
1 #include <string.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5 #include <assert.h>
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9
10 //服务器与客户端的循环实现
11 int main()
12 {
13 int sockfd = socket(AF_INET, SOCK_STREAM, 0);
14 assert(sockfd != -1);
15 struct sockaddr_in saddr;
16 memset(&saddr, 0, sizeof(saddr));
17 saddr.sin_family = AF_INET;
18 saddr.sin_port = htons(6001);
19 saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
20
21 int res = connect(sockfd,(struct sockaddr*)&saddr, sizeof(saddr));
22 assert(res != -1);
23
24 while(1)
25 {
26 char buff[128] = {0};
27 printf("input:\n");
28 fgets(buff,128,stdin);
29 if(strncmp(buff,"end",3) == 0)
30 {
31 break;
32 }
33 send(sockfd, buff, strlen(buff), 0);
34 memset(buff, 0, 128);
35 recv(sockfd, buff, 127, 0);//127改为1，表示一个一个接收
36 printf("buff=%s\n",buff);
37 }
38 close(sockfd);
39 exit(0);
40 }