【求教】怎么用c语言来判断网络是否通
比如 用ping 192.168.1.12 让c语言判断 是通还是不通怎么来实现 c 网络
[解决办法]
仅供参考

#include <windows.h>
#include <stdio.h>
char cmdstr[256];
int i;
int YN(int k) {
    FILE *f;
    char fn[40];
    char ln[80];
    int yn=0;

    sprintf(fn,"d:\\ping%d.txt",k);
    f=fopen(fn,"r");
    if (NULL!=f) {
        fgets(ln,80,f);
        fgets(ln,80,f);
        fgets(ln,80,f);
        if (1==fscanf(f,"Re%c",&yn)) yn='q'-yn;
        fclose(f);
        unlink(fn);
    }
    return yn;
}
void main() {
    for (i=115;i<130;i++) {
        sprintf(cmdstr,"cmd /c ping 192.168.2.%d -n 1 -w 1000 >d:\\ping%d.txt",i,i);
        WinExec(cmdstr,SW_HIDE);
    }
    Sleep(3000);
    for (i=115;i<130;i++) {
        printf("%d 192.168.2.%d\n",YN(i),i);
    }
}
//1 192.168.2.115
//0 192.168.2.116
//0 192.168.2.117
//0 192.168.2.118
//1 192.168.2.119
//0 192.168.2.120
//0 192.168.2.121
//0 192.168.2.122
//1 192.168.2.123
//0 192.168.2.124
//0 192.168.2.125
//1 192.168.2.126
//0 192.168.2.127
//1 192.168.2.128
//0 192.168.2.129

[解决办法]
int Ping(LPCSTR pstrHost)
{
int nErrorNum=0;

SOCKET rawSocket;
LPHOSTENT lpHost;
struct sockaddr_in saDest;
struct sockaddr_in saSrc;
DWORD dwTimeSent;
DWORD dwElapsed;
u_char cTTL;
int nLoop;
int nRet;

// Create a Raw socket
rawSocket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (rawSocket == SOCKET_ERROR)
{
ReportError("socket()");
return -1;
}

// Lookup host
lpHost = gethostbyname(pstrHost);
if (lpHost == NULL)
{
fprintf(stderr,"\nHost not found: %s\n", pstrHost);
return -2;
}

// Setup destination socket address
saDest.sin_addr.s_addr = *((u_long FAR *) (lpHost->h_addr));
saDest.sin_family = AF_INET;
saDest.sin_port = 0;

// Tell the user what we're doing
printf("\nPinging %s [%s] with %d bytes of data:\n",
pstrHost,
inet_ntoa(saDest.sin_addr),
REQ_DATASIZE);

// Ping multiple times

for (nLoop = 0; nLoop < 2; nLoop++) //原来为4
{
// Send ICMP echo request
SendEchoRequest(rawSocket, &saDest);

// Use select() to wait for data to be received
nRet = WaitForEchoReply(rawSocket);
if (nRet == SOCKET_ERROR)
{
ReportError("select()");
nErrorNum = nErrorNum+1;
break;
}
if (!nRet)
{
printf("\nTimeOut");
nErrorNum = nErrorNum+1;
break;
}

// Receive reply
dwTimeSent = RecvEchoReply(rawSocket, &saSrc, &cTTL);

// Calculate elapsed time
dwElapsed = GetTickCount() - dwTimeSent;
printf("\nReply from: %s: bytes=%d time=%ldms TTL=%d",
inet_ntoa(saSrc.sin_addr),
REQ_DATASIZE,
dwElapsed,
cTTL);
}
printf("\n");
nRet = closesocket(rawSocket);
if (nRet == SOCKET_ERROR)
ReportError("closesocket()");

return nErrorNum;
}
[解决办法]
1。网上有 ping 的原代码，但在 win7 下有 权限问题
2。 system ("ping 127.0.0.1 > 1.txt"); 分析 1.txt