op server client 소켓통신 소스코드

client.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 1024
#define RLT_SIZE 4
#define OPSZ 4
void error_handling(char *message);

int main(int argc, char *argv[])
{
	int sock;
	char opmsg[BUF_SIZE];
	int result, opnd_cnt, i;
	struct sockaddr_in serv_adr;
	if(argc!=3)
	{
		printf("Usage : %s <IP> <port>\n", argv[0]);
		exit(1);
	}

	sock = socket(PF_INET, SOCK_STREAM, 0);
	if(sock ==-1)
		error_handling("socket() error");

	memset(&serv_adr, 0, sizeof(serv_adr));
	serv_adr.sin_family = AF_INET;
	serv_adr.sin_addr.s_addr = inet_addr(argv[1]);
	serv_adr.sin_port = htons(atoi(argv[2]));

	if(connect(sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr)) ==1)
		error_handling("connect() error");

	else
		puts("Connected...............");

	fputs("Operand count : ", stdout);
	scanf("%d", &opnd_cnt);
	opmsg[0] = (char)opnd_cnt;

	for(i = 0; i < opnd_cnt; i++)
	{
		printf("Operand %d : ", i+1);
		scanf("%d", (int*)&opmsg[i*OPSZ+1]);
	}
	fgetc(stdin);
	fputs("Operator : ", stdout);
	scanf("%c", &opmsg[opnd_cnt*OPSZ+1]);
	write(sock, opmsg, opnd_cnt*OPSZ+2);
	read(sock, &result, RLT_SIZE);
	
	printf("Operation result : %d \n", result);
	
	close(sock);
	return 0;
}
void error_handling(char *message)
{
	fputs(message, stderr);
	fputc('\n', stderr);
	exit(1);
}

server.c

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#define BUF_SIZE 1024
#define RLT_SIZE 4
#define OPSZ 4
void error_handling(char * message);
int calculate(int opnum, int opnds[], char oprator);
int main(int argc, char *argv[])
{
        int sizeo;
        int serv_sock, clnt_sock;
        char opinfo[BUF_SIZE];
        int result, opnd_cnt, i;
        int recv_cnt, recv_len;
        struct sockaddr_in serv_adr, clnt_adr;
        socklen_t clnt_adr_sz;
        if(argc !=2){
        printf("Usage : %s <port>\n", argv[0]);
        exit(1);
        }
        serv_sock = socket(PF_INET, SOCK_STREAM, 0);
        if(serv_sock == -1)
                error_handling("socket() error");

        memset(&serv_adr, 0, sizeof(serv_adr));
        serv_adr.sin_family = AF_INET;
        serv_adr.sin_addr.s_addr = htonl(INADDR_ANY);
        serv_adr.sin_port = htons(atoi(argv[1]));
        if(bind(serv_sock,(struct sockaddr *)&serv_adr, sizeof(serv_adr)) == -1)
                error_handling("bind() error");
        if(listen(serv_sock, 5) == -1)
                error_handling("listen() error");
        clnt_adr_sz = sizeof(clnt_adr);

        for(i=0; i<5; i++)
        {
                opnd_cnt = 0;
                clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_adr, &clnt_adr_sz);
                read(clnt_sock, &opnd_cnt, 1);

                recv_len = 0;
                while((opnd_cnt*OPSZ+1)>recv_len)
                {
                        recv_cnt = read(clnt_sock, &opinfo[recv_len], BUF_SIZE-1);
                        recv_len += recv_cnt;
                }
                result = calculate(opnd_cnt, (int*)opinfo, opinfo[recv_len -1]);
                write(clnt_sock, (char *)&result, sizeof(result));
                close(clnt_sock);
        }
        close(serv_sock);
        return 0;

}

int calculate(int opnum, int opnds[], char op)
{
        int result = opnds[0], i;
        switch(op)
        {
                case '+':
                        for(i=1; i<opnum; i++) result += opnds[i];
			break;
		case '-':
			for(i=1; i<opnum; i++) result -= opnds[i];
			break;
		case '*':
			for(i=1; i<opnum; i++)  result *= opnds[i];
			break;
		case '%':
			for(i=1; i<opnum; i++)  result %= opnds[i];
			break;
		case '/':
			for(i=1; i<opnum; i++)  result /= opnds[i];
			break;
		}
		return result;
}

void error_handling(char *message)
{
	fputs(message, stderr);
	fputc('\n', stderr);
	exit(1);
}