我正在尝试创建一个简单的基于客户端/服务器套接字的程序。它只是一个基本的＆＃34;猜数字＆＃34;游戏，服务器提供一个数字，然后客户端尝试猜测数字。问题是我遇到了按预期工作的程序问题。
问题是这样的：当我启动服务器程序并生成随机数时，我尝试加载客户端程序，但在一次输入后，它们就会停止工作。输出后会停止：
Guess: 42
Buffer to be processed : <42
>
integerGuess : <42>
String Guess : <42\n>
Buffer to send : <42\n>
这是server.c文件代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <time.h> /* time for randomizer*/
void error(const char *msg)
{
perror(msg);
exit(1);
}
int main(int argc, char *argv[])
{
int sockfd, newsockfd, portno, n;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
int GuessedInteger, integerRandom, serverFlagCorrect;
char charGuess[4], answerServer[1];
char* delimiter = "\\n";
/** initialization of variables **/
serverFlagCorrect = 0;
/** generate random integer from 1 to 100 **/
srand (time(NULL));
integerRandom = (rand() % 100) + 1;
printf("This is the random integer : %d \n", integerRandom);
if (argc < 2) {
fprintf(stderr,"ERROR, no port provided\n");
exit(1);
}
// Creates the socket socket() --> endpoints of sockets
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
// Creates the socket socket() --> endpoints of sockets
// assign unique new address
bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(portno);
if (bind(sockfd, (struct sockaddr *) &serv_addr,
sizeof(serv_addr)) < 0)
error("ERROR on binding");
// assign unique new address
// wait for a connection
listen(sockfd,5);
// wait for a connection
// accepts the connection
clilen = sizeof(cli_addr);
while (1) {
newsockfd = accept(sockfd,
(struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0)
error("ERROR on accept");
n = fork();
if (n < 0)
error("ERROR on fork");
if (n == 0) {
close(sockfd);
dostuff(newsockfd);
exit(0);
}
else close(newsockfd);
} /* end of while */
close(sockfd);
return 0; /* we never get here */
}
void dostuff (int sock) {
int GuessedInteger, integerRandom, serverFlagCorrect;
char charGuess[4], answerServer[1];
char* delimiter = "\\n";
int sockfd, newsockfd, portno, n;
socklen_t clilen;
char buffer[256];
struct sockaddr_in serv_addr, cli_addr;
while (serverFlagCorrect != 1)
{
// reads the data being received
bzero(buffer,256);
n = read(newsockfd,buffer,255);
if (n < 0) error("ERROR reading from socket");
// reads the data being received
printf("Buffer from client: <%s>\n", buffer);
memcpy(charGuess, buffer, sizeof(charGuess));
printf("Message from client in charGuess: <%s>\n", charGuess);
/* Put if statement here for error out if no \n at the end */
int len = strlen(charGuess);
const char *last_two = &charGuess[len-2];
printf("Last two characters of charGuess: <%s>\n", last_two);
if (strncmp ( last_two, delimiter, 2) )
error (" ERROR Wrong protocol received");
/** turn string to int for comparison **/
GuessedInteger = atoi(charGuess);
printf("Guessed Integer : %d \n", GuessedInteger);
/** Server response for comparison**/
if (GuessedInteger > integerRandom)
memcpy(&answerServer, "Lower", sizeof(answerServer));
else if (GuessedInteger < integerRandom)
memcpy(&answerServer, "Higher", sizeof(answerServer));
else if (GuessedInteger == integerRandom)
{
serverFlagCorrect = 1;
memcpy(&answerServer, "Correct", sizeof(answerServer));
}
printf("Value of answerServer: %c\n", *answerServer);
/** Server response for comparison**/
// sends the answer
n = write(newsockfd, answerServer, 1);
if (newsockfd < 0)
error("ERROR on accept");
// sends the answer
// closes what was sent
}
close(newsockfd);
}
这是client.c代码：
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
void error(const char *msg)
{
perror(msg);
exit(0);
}
int main(int argc, char *argv[])
{
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[1024];
int integerGuess, clientFlagCorrect;
int numberOfTries;
char charGuess[1024], answerServer[1];
char* delimiter = "\\n";
if (argc < 3) {
fprintf(stderr,"usage %s hostname port\n", argv[0]);
exit(0);
}
portno = atoi(argv[2]);
// Creates the socket socket() --> endpoints of sockets
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
// Creates the socket socket() --> endpoints of sockets
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr,"ERROR, no such host\n");
exit(0);
}
// connects to the service in connect()
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy((char *)server->h_addr,
(char *)&serv_addr.sin_addr.s_addr,
server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
error("ERROR connecting");
// connects to the service
/** variables **/
clientFlagCorrect = 0;
numberOfTries = 0;
while (clientFlagCorrect != 1)
{
numberOfTries = numberOfTries + 1;
/** initializing vars **/
integerGuess = 0;
memset(charGuess, 0, sizeof(charGuess));
// ask for the number
printf("Guess: ");
bzero(buffer,sizeof(buffer));
fgets(buffer,sizeof(buffer)-1,stdin);
printf("Buffer to process is : <%s>\n", buffer);
// ask to see if the number is guessed
/** string and delimeter **/
integerGuess = atoi(buffer);
printf("int Guess : <%d> \n", integerGuess);
sprintf( charGuess, "%d", integerGuess);
strcat( charGuess, delimiter);
printf("String Guess : <%s> \n", charGuess);
memset(buffer,0,sizeof(buffer));
memcpy(buffer, charGuess, sizeof(charGuess));
printf("Buffer to be sent is: : <%s>\n",buffer);
/** process the integer to string and add a delimiter **/
// send the string that was processed
n = write(sockfd,buffer,strlen(buffer));
if (n < 0)
error("ERROR writing to socket");
// send the string that was processed
// reads the data being received
bzero(buffer,256);
n = read(sockfd,buffer,255);
if (n < 0)
error("ERROR reading from socket");
// reads the data being received
printf("Buffer received : <%s>\n",buffer);
memcpy(&answerServer, buffer, sizeof(answerServer));
printf ("Value of answerServer : <%c> \n", *answerServer);
/** Client response **/
if (strncmp ( & answerServer[0],"Lower",sizeof(answerServer)) == 0)
printf("The number is lower \n");
else if (strncmp ( & answerServer[0],"Higher",sizeof(answerServer)) == 0)
printf("The number is higher \n");
else if (strncmp ( & answerServer[0],"Correct",sizeof(answerServer)) == 0)
{
printf("Your guess is correct! \n");
clientFlagCorrect = 1;
}
else
error("ERROR Wrong message received");
}
printf ("It took you this many tries: %d \n", numberOfTries);
printf("%s\n",buffer);
close(sockfd);
return 0;
}
非常感谢任何帮助。
编辑：经过一些额外的工作和＆＃34;调试＆＃34; （主要由我在各个点添加一些printf）我90％确信问题出在服务器端。我在此行之前和之后添加了printf＆＃39; printf（＆＃34;这是随机整数：％d \ n＆＃34;，integerRandom）; 并且发现虽然紧接在行之前的printf打印出来的很好，但是如果打印出＆＃34;没有检测到端口＆＃34错误。任何进一步的printf根本不会触发，这意味着程序甚至无法到达执行程序的主循环。
至于客户端文件，它到达了这一行： printf（＆＃34;要发送的缓冲区是::＆lt;％s＆gt; \ n＆＃34;，缓冲区）; 并停止（再次通过printf＆＃39; s）。为什么，老实说，我没有任何线索。这意味着围绕这些点存在问题，但在哪里，老实说我没有任何线索。