select공부중인데...어디가 잘못된건가요??

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/time.h>
#include<sys/socket.h>
#include<netinet/in.h>
 
#define PORT 8888
#define BUFSIZE 128
 
int main(int argc, char **argv)
{
        int serv_sock;
        struct sockaddr_in serv_addr;
 
        fd_set reads, temps;
        int fd_max;
 
        char message[BUFSIZE];
        int str_len;
        struct timeval timeout;
 
        if(argc !=1 ) {
                printf("Usage : %s \n", argv[0]);
                exit(1);
        }
 
        serv_sock=socket(PF_INET, SOCK_STREAM, 0);
        serv_addr.sin_family=AF_INET;
        serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
        serv_addr.sin_port=htons(PORT);
 
        if(bind(serv_sock,(struct sockaddr *) &serv_addr, sizeof(serv_addr)))
        {
                printf("bind() error\n");
                exit(1);
        }
        if(listen(serv_sock,5)==-1)
        {
                printf("listen() error\n");
                exit(1);
        }
 
        FD_ZERO(&reads);
        FD_SET(serv_sock,&reads);
        fd_max=serv_sock;
 
        while(1)
        {
                int fd, str_len;
                int clnt_sock, clnt_len;
                struct sockaddr_in clnt_addr;
 
                temps=reads;
                timeout.tv_sec=5;
                timeout.tv_usec=0;
 
                if(select(fd_max+1, &temps, 0,0, &timeout)==-1)
                {
                        printf("select() error\n");
                        exit(1);
                }
                for(fd=0; fd<fd_max+1; fd++)
                {
                        if(FD_ISSET(fd,&temps))
                        {
                                if(fd==serv_sock)
                                {
                                        clnt_len=sizeof(clnt_addr);
                                        clnt_sock=accept(serv_sock,(struct sockaddr *)&clnt_addr, &clnt_len);
                                        FD_SET(clnt_sock,&reads);
                                        if(fd_max<clnt_sock)
                                                fd_max=clnt_sock;
                                        printf("클라이언트 연결 : 파일디스크립터 %d \n", clnt_sock);
                                }
                                else
                                {
                                        str_len=read(fd,message,BUFSIZE);
                                        if(str_len=0)
                                        {
                                                FD_CLR(fd,&reads);
                                                close(fd);
                                                printf("클라이언트 종료 : 파일디스크립터 %d\n", fd);
                                        }
                                        else
                                        {
                                                write(fd,message, str_len);
                                        }
                                }
                        }
                }
        }
}

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<sys/socket.h>
 
#define PORT 8888
#define BUFSIZE 128
 
int main(int argc, char **argv)
{
        int sock;
        char message[BUFSIZE];
        int str_len;
        struct sockaddr_in serv_addr;
 
        if(argc !=2)
        {
                printf("Usage : %s <IP>\n",argv[0]);
                exit(1);
        }
        sock=socket(PF_INET, SOCK_STREAM, 0);
        if(sock==-1)
        {
                printf("socket() error\n");
                exit(1);
        }
        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family=AF_INET;
        serv_addr.sin_addr.s_addr=inet_addr(argv[1]);
        serv_addr.sin_port=htons(PORT);
 
        if(connect(sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
        {
                printf("connect() error\n");
                exit(1);
        }
        while(1)
        {
                fputs("전송할 메시지를 입력하세요 (q to quit) : ", stdout);
                fgets(message, BUFSIZE, stdin);
 
                if(!strcmp(message, "q\n"))
                        break;
                write(sock, message, strlen(message));
 
                str_len=read(sock, message, BUFSIZE-1);
                message[str_len]=0;
                printf("서버로부터 전송된 메시지 : %s\n",message);
        }
        close(sock);
        return 0;
}