c-最后一个元素不出现

Question

练习要求将消息重新发送回客户端。

这个包含一些代码的练习是由我们的老师提供的

我不知道为什么程序发送的最后一条消息没有出现。我不明白错误在哪里。

我更改了阅读内容，添加了&x之前。现在x值正确显示，但最后一个值仍然丢失

当我只插入一个值时，消息就会丢失。服务器一直在运行，我不知道如何解决这个问题。

服务器代码为：

#include <stdio.h>      
#include <sys/types.h>
#include <sys/socket.h>   
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h> 
/*const*/ char MESSAGE[100] = "";
char buff[100];
int main(int argc, char *argv[]) {
int simpleSocket = 0;
int simplePort = 0;
int returnStatus = 0;
struct sockaddr_in simpleServer;

if (argc != 2) {
fprintf(stderr, "Usage: %s <port>n", argv[0]);
exit(1);
}
simpleSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (simpleSocket == -1) {
fprintf(stderr, "Could not create a socket!n");
exit(1);
}
else {
fprintf(stderr, "Socket created!n");
}
/* retrieve the port number for listening */
simplePort = atoi(argv[1]);
/* setup the address structure */
/* use INADDR_ANY to bind to all local addresses  */
memset(&simpleServer, '', sizeof(simpleServer)); 
simpleServer.sin_family = AF_INET;
simpleServer.sin_addr.s_addr = htonl(INADDR_ANY);
simpleServer.sin_port = htons(simplePort);
/*  bind to the address and port with our socket  */
returnStatus = bind(simpleSocket,(struct sockaddr *)&simpleServer,sizeof(simpleServer));
if (returnStatus == 0) {
fprintf(stderr, "Bind completed!n");
}
else {
fprintf(stderr, "Could not bind to address!n");
close(simpleSocket);
exit(1);
}
/* lets listen on the socket for connections      */
returnStatus = listen(simpleSocket, 5);
if (returnStatus == -1) {
fprintf(stderr, "Cannot listen on socket!n");
close(simpleSocket);
exit(1);
}
int x;
int i=0;
while (1)
{
struct sockaddr_in clientName = { 0 };
int simpleChildSocket = 0;
int clientNameLength = sizeof(clientName);
/* wait here */
simpleChildSocket = accept(simpleSocket,(struct sockaddr *)&clientName, &clientNameLength);
if (simpleChildSocket == -1) {
fprintf(stderr, "Cannot accept connections!n");
close(simpleSocket);
exit(1);
}
/* handle the new connection request  */
/* write out our message to the client */

//read the number of messages that have to be send
read(simpleChildSocket, &x, sizeof(x));
printf("x value is: %dn", x);

do{
// read the message from client and copy it in buffer 
read(simpleChildSocket, buff, sizeof(buff));
//copy buff in MESSAGE
strcpy(MESSAGE, buff);
//sending the message
write(simpleChildSocket, MESSAGE, strlen(MESSAGE));

//cleaning the buffer
memset(&simpleServer, '', sizeof(simpleServer));
i++;
}while(i<x);

close(simpleChildSocket);
}
close(simpleSocket);
return 0;
}

客户端代码为：

#include <stdio.h>      
#include <sys/types.h>
#include <sys/socket.h>   
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
int main(int argc, char *argv[]) {
int simpleSocket = 0;
int simplePort = 0;
int returnStatus = 0;
char buffer[256] = "";
struct sockaddr_in simpleServer;
if (argc != 3) {
fprintf(stderr, "Usage: %s <server> <port>n", argv[0]);
exit(1);
}
/* create a streaming socket      */
simpleSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (simpleSocket == -1) {
fprintf(stderr, "Could not create a socket!n");
exit(1);
}
else {
fprintf(stderr, "Socket created!n");
}
/* retrieve the port number for connecting */
simplePort = atoi(argv[2]);
/* setup the address structure */
/* use the IP address sent as an argument for the server address  */
//bzero(&simpleServer, sizeof(simpleServer)); 
memset(&simpleServer, '', sizeof(simpleServer));
simpleServer.sin_family = AF_INET;
//inet_addr(argv[2], &simpleServer.sin_addr.s_addr);
simpleServer.sin_addr.s_addr=inet_addr(argv[1]);
simpleServer.sin_port = htons(simplePort);
/*  connect to the address and port with our socket  */
returnStatus = connect(simpleSocket, (struct sockaddr *)&simpleServer, sizeof(simpleServer));
if (returnStatus == 0) {
fprintf(stderr, "Connect successful!n");
}
else {
fprintf(stderr, "Could not connect to address!n");
close(simpleSocket);
exit(1);
}
/*create the message*/
char buff[100];
int i=0, x;
//int n;
//while((buff[n++] = getchar()) != 'n');
printf("How many messages do you want to send?n");
scanf("%d", &x);
write(simpleSocket, x, sizeof(x));
printf("Insert the message:n");
do{
fgets(buff, 100, stdin);
write(simpleSocket, buff, sizeof(buff));
i++;
}while(i<=x);
/* get the message from the server   */
returnStatus = read(simpleSocket, buffer, sizeof(buffer));
if ( returnStatus > 0 ) {
printf("%d: %s", returnStatus, buffer);
} else {
fprintf(stderr, "Return Status = %d n", returnStatus);
}
close(simpleSocket);
return 0;
}

Answer 1

您的read有问题。这应该是：

read(simpleChildSocket, &x, sizeof(x));

Read需要一个指针。