服务器端：
1: #include
2: #include
3: #include
4: #include
5: #include
6: #include
7: #include
8: #include
9: #include
10:
11: typedef struct sockaddr SA;
12: #define N 256
13:
14: int main(int argc, char *argv[])
15: { 16: int sockfd;
17: char buffer[N];
18: char buffer2[N];
19: struct sockaddr_in myaddr, peeraddr;
20: socklen_t peerlen = sizeof(peeraddr);
21: int maxfd;
22: int i;
23:
24: fd_set rdfs;
25:
26: if((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
27: { 28: perror("fail to socket"); 29: exit(-1);
30: }
31:
32: bzero(&myaddr, sizeof(myaddr));
33: myaddr.sin_family = PF_INET;
34: myaddr.sin_port = htons(atoi(argv[2]));
35: myaddr.sin_addr.s_addr = inet_addr(argv[1]);
36:
37: if(bind(sockfd, (SA *)&myaddr, sizeof(myaddr)) < 0)
38: { 39: perror("fail to bind"); 40: exit(-1);
41: }
42:
43: bzero(&peeraddr, peerlen);
44: maxfd = sockfd;
45:
46:
47: while(1)
48: { 49: FD_ZERO(&rdfs);
50: FD_SET(0, &rdfs);
51: FD_SET(sockfd, &rdfs);
52:
53: select(maxfd+1, &rdfs, NULL, NULL, NULL);
54:
55: for(i=0; i<=maxfd; i++)
56: { 57: if(FD_ISSET(i, &rdfs) == 1)
58: { 59: if(i == 0)
60: { 61: fgets(buffer2, N, stdin);
62: printf("you input %s", buffer2); 63: }
64: if(i == sockfd)
65: { 66: recvfrom(sockfd, buffer, N, 0, (SA *)&peeraddr, &peerlen);
67: sendto(sockfd, buffer, N, 0, (SA *)&peeraddr, peerlen);
68: }
69: }
70: }
71:
72: }
73:
74: return 0;
75: }
客户端：
1: #include
2: #include
3: #include
4: #include
5: #include
6: #include
7: #include
8:
9: typedef struct sockaddr SA;
10: #define N 256
11:
12: int main(int argc, char *argv[])
13: { 14: int sockfd;
15: char buffer[N];
16: struct sockaddr_in serveraddr;
17:
18: if((sockfd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
19: { 20: perror("fail to socket"); 21: exit(-1);
22: }
23:
24: bzero(&serveraddr, sizeof(serveraddr));
25: serveraddr.sin_family = PF_INET;
26: serveraddr.sin_port = htons(atoi(argv[2]));
27: serveraddr.sin_addr.s_addr = inet_addr(argv[1]);
28:
29: while(1)
30: { 31: fgets(buffer, N, stdin);
32: if(strncmp(buffer, "quit", 4) == 0)
33: { 34: break;
35: }
36: sendto(sockfd, buffer, N, 0, (SA *)&serveraddr, sizeof(serveraddr));
37: bzero(buffer, N);
38: recvfrom(sockfd, buffer, N, 0, NULL, NULL);
39: printf("receive from server > %s",buffer); 40: }
41: close(sockfd);
42: return 0;
43: }
运行：