C++ C++；奇怪的套接字数据

嘿，伙计们，这是我的密码

int main() { 

    char buffer[BUFSIZE]; 

    // define our address structure, stores our port
    // and our ip address, and the socket type, etc.. 
    struct sockaddr_in addrinfo; 
    addrinfo.sin_family = AF_INET; 
    addrinfo.sin_port = htons(PORT); 
    addrinfo.sin_addr.s_addr = INADDR_ANY; 


    // create our socket. 
    int sock; 
    if ( (sock = socket(addrinfo.sin_family, SOCK_STREAM, 0))  < 0) { 
        cout << "Error in creating the socket."; 
    } 

    // bind our socket to the actual adress we want 
    if (bind(sock, (struct sockaddr*)&addrinfo, sizeof(addrinfo)) != 0) { 
        cout << "Error in binding."; 
    } 

    // open the socket up for listening
    if (listen(sock, 5) != 0) { 
        cout << "Error in opening listener."; 
    } 
    cout << "Waiting for connections...." << endl; 

    char *msg = "Success! You are connected.\r\n"; 

    // continuously accept new connections.. but no multithreading.. yet
    while(1) { 

        struct sockaddr_in client_addr;
        socklen_t sin_size = sizeof(client_addr); 

        if(int client = accept(sock, (struct sockaddr*)&client_addr, &sin_size)) { 
            cout << "Recived new connection from " << inet_ntoa(client_addr.sin_addr) << endl; 
            send(client, msg, strlen(msg), 0); 
            while(1) { 
                send(client, buffer, recv(client, buffer, BUFSIZE, 0), 0);

                cout << buffer << endl; 
                strcpy(buffer, ""); 
            } 

        } else { 
            cout << "Error in accepting new connection." << endl; 
        } 

    } 

    close(sock); 
    return 0; 
} 

int main（）{
字符缓冲区[BUFSIZE]；
//定义我们的地址结构，存储我们的端口
//以及我们的ip地址和套接字类型等。。
addrinfo中的结构sockaddr_；
addrinfo.sin_family=AF_INET；
addrinfo.sinu port=htons（端口）；
addrinfo.sin\u addr.s\u addr=INADDR\u ANY；
//创建我们的套接字。
int袜子；
如果（（sock=socket（addrinfo.sin_族，sock_流，0））<0）{
cout问题是
buffer
不保证包含以字符串结尾的空字符。在
cout之前添加行
buffer[BUFSIZE-1]='\0'
问题是
buffer
不保证包含以字符串结尾的空字符。添加行
buffer[BUFSIZE-1]='\0'
就在您的
cout之前，因为
recv
不为null，所以您的缓冲区被打印出来

以下代码中的重要部分是：

int num = recv(client,buffer,BUFSIZE,0);
if (num < 1) break;

send(client, ">> ", 3, 0);     // <<-- Nice to have.
send(client, buffer, num, 0);

buffer[num] = '\0';            // <<-- Really important bit!

if (buffer[num-1] == '\n')     // <<-- Nice to have.
    buffer[num-1] = '\0';      // <<-- Nice to have.

cout << buffer << endl;

由于
recv
不为null并终止缓冲区，所以打印出来的内容都是垃圾

以下代码中的重要部分是：

int num = recv(client,buffer,BUFSIZE,0);
if (num < 1) break;

send(client, ">> ", 3, 0);     // <<-- Nice to have.
send(client, buffer, num, 0);

buffer[num] = '\0';            // <<-- Really important bit!

if (buffer[num-1] == '\n')     // <<-- Nice to have.
    buffer[num-1] = '\0';      // <<-- Nice to have.

cout << buffer << endl;

嗯，我理解你对空字符的看法。但它似乎不起作用。我仍然得到奇怪的字符输出。我肯定不会用四个字母的字符串溢出缓冲区变量，是吗？你需要使用
recv
的返回值来存储nul字节，否则就是“hello”的recv后跟另一个“x”将给出“xello”（在这两种情况下，加上缓冲区中超过第五个字节（直到末尾）的垃圾）.hmm我理解你对空字符的看法。但它似乎不起作用。我仍然得到奇怪的字符输出。我肯定不会用四个字母的字符串溢出缓冲区变量，对吗？你需要使用
recv
的返回值来存储nul字节，否则就是“hello”的recv后跟另一个“x”将给出“xello”（在这两种情况下，加上缓冲区中超过第五个字节（直到末尾）的垃圾）。是，如果另一端关闭连接，则错误为-1；如果另一端关闭连接，则错误为0；如果另一端关闭连接，则错误为-1；如果另一端关闭连接，则错误为-0；如果另一端关闭连接，则错误为-1；如果另一端关闭连接，则错误为-1；如果另一端关闭连接，则错误为-0；如果另一端关闭连接，则错误为-1；如果另一端关闭连接。
$ telnet 127.0.0.1 1234
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Success! You are connected.
hello
>> hello
my name is pax
>> my name is pax
and you?
>> and you?
<CTRL-D>
Connection closed by foreign host.

$ ./testprog
Waiting for connections....
Recived new connection from 127.0.0.1
hello
my name is pax
and you?
Waiting for connections....