#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>

int main() {
struct sockaddr_in server, client={AF_INET,INADDR_ANY,INADDR_ANY};
memset(&server,0,sizeof(server));
server.sin_family=AF_INET;
server.sin_port=htons(1212);
server.sin_addr.s_addr=inet_addr("127.0.0.1");

int sock;
sock=socket(PF_INET,SOCK_DGRAM,0);
bind(sock,(sockaddr *) & client,sizeof(client));

char buf[81];
memset(buf,0,81);
strcpy(buf,"request");
sendto(sock,&buf,strlen(buf),0,(sockaddr *)&server,sizeof(server));
memset(buf,0,81);
recvfrom(sock,buf,80,0,NULL,0);
puts(buf);

return 0;
}

laptop:~/C/tc$ gcc -o udpcl udpcl.c
udpcl.c: In function ‘main’:
udpcl.c:18: error: ‘sockaddr’ undeclared (first use in this function)
udpcl.c:18: error: (Each undeclared identifier is reported only once
udpcl.c:18: error: for each function it appears in.)
udpcl.c:18: error: expected expression before ‘)’ token
udpcl.c:18: error: too few arguments to function ‘bind’
udpcl.c:23: error: expected expression before ‘)’ token
udpcl.c:23: error: too few arguments to function ‘sendto’