关于网络编程的问题,郁闷中....
// Command Line Options:
// client [-p:x] [-s:IP] [-n:x] [-o]
// -p:x Remote port to send to
// -s:IP Server 's IP address or hostname
// -n:x Number of times to send message
// -o Send messages only; don 't receive
//
#include <winsock2.h>
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_COUNT 20
#define DEFAULT_PORT 5150
#define DEFAULT_BUFFER 2048
#define DEFAULT_MESSAGE "This is a test of the emergency \
broadcasting system "
char szServer[128], // Server to connect to
szMessage[1024]; // Message to send to sever
int iPort = DEFAULT_PORT; // Port on server to connect to
DWORD dwCount = DEFAULT_COUNT; // Number of times to send message
BOOL bSendOnly = FALSE; // Send data only; don 't receive
//
// Function: usage:
//
// Description:
// Print usage information and exit
//
void usage()
{
printf( "usage: client [-p:x] [-s:IP] [-n:x] [-o]\n\n ");
printf( " -p:x Remote port to send to\n ");
printf( " -s:IP Server 's IP address or hostname\n ");
printf( " -n:x Number of times to send message\n ");
printf( " -o Send messages only; don 't receive\n ");
ExitProcess(1);
}
//
// Function: ValidateArgs
//
// Description:
// Parse the command line arguments, and set some global flags
// to indicate what actions to perform
//
void ValidateArgs(int argc, char **argv)
{
int i;
for(i = 1; i < argc; i++)
{
if ((argv[i][0] == '- ') || (argv[i][0] == '/ '))
{
switch (tolower(argv[i][1]))
{
case 'p ': // Remote port
if (strlen(argv[i]) > 3)
iPort = atoi(&argv[i][3]);
break;
case 's ': // Server
if (strlen(argv[i]) > 3)
strcpy(szServer, &argv[i][3]);
break;
case 'n ': // Number of times to send message
if (strlen(argv[i]) > 3)
dwCount = atol(&argv[i][3]);
break;
case 'o ': // Only send message; don 't receive
bSendOnly = TRUE;
break;
default:
usage();
break;
}
}
}
}
//
// Function: main
//
// Description:
// Main thread of execution. Initialize Winsock, parse the
// command line arguments, create a socket, connect to the
// server, and then send and receive data.
//
int main(int argc, char **argv)
{
WSADATA wsd;
SOCKET sClient;
char szBuffer[DEFAULT_BUFFER];
int ret,
i;
struct sockaddr_in server;
struct hostent *host = NULL;
// Parse the command line and load Winsock
//
ValidateArgs(argc, argv);
if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
{
printf( "Failed to load Winsock library!\n ");
return 1;
}
strcpy(szMessage, DEFAULT_MESSAGE);
//
// Create the socket, and attempt to connect to the server
//
sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sClient == INVALID_SOCKET)
{
printf( "socket() failed: %d\n ", WSAGetLastError());
return 1;
}
server.sin_family = AF_INET;
server.sin_port = htons(iPort);
server.sin_addr.s_addr = inet_addr(szServer);
//
// If the supplied server address wasn 't in the form
// "aaa.bbb.ccc.ddd " it 's a hostname, so try to resolve it
//
if (server.sin_addr.s_addr == INADDR_NONE)
{
host = gethostbyname(szServer);
if (host == NULL)
{
printf( "Unable to resolve server: %s\n ", szServer);
return 1;
}
CopyMemory(&server.sin_addr, host-> h_addr_list[0],
host-> h_length);
}
if (connect(sClient, (struct sockaddr *)&server,
sizeof(server)) == SOCKET_ERROR)
{
printf( "connect() failed: %d\n ", WSAGetLastError());
return 1;
}
// Send and receive data
//
for(i = 0; i < dwCount; i++)
{
ret = send(sClient, szMessage, strlen(szMessage), 0);
if (ret == 0)
break;
else if (ret == SOCKET_ERROR)
{
printf( "send() failed: %d\n ", WSAGetLastError());
break;
}
printf( "Send %d bytes\n ", ret);
if (!bSendOnly)
{
ret = recv(sClient, szBuffer, DEFAULT_BUFFER, 0);
if (ret == 0) // Graceful close
break;
else if (ret == SOCKET_ERROR)
{
printf( "recv() failed: %d\n ", WSAGetLastError());
break;
}
szBuffer[ret] = '\0 ';
printf( "RECV [%d bytes]: '%s '\n ", ret, szBuffer);
}
}
closesocket(sClient);
WSACleanup();
return 0;
}
在ValidateArgs函数中有这样几句
case 's ': // Server
if (strlen(argv[i]) > 3)
strcpy(szServer, &argv[i][3]);
break;
这不是只把argv中第i个字符串的第4个字母放到szServer里去吗
但是我在运行时,只有填完整的服务器IP(当然是正确的)才会连接到服务器上，这是哪门子事呀.......
[解决办法]
strcpy,从argv[i]的第四个字母到字符串的结束.
字符串的结束标志是 '\0 '.
