为什么我在接收的包装结束时会获得Gibberish文本？

Question

我正在为大学做一个激光雷达项目，但我遇到了一点困难。我正在发送一个包裹，其中包括电机的确切位置以及通过 WiFi 从距离传感器读取的距离，包裹应该看起来像这样的“位置/距离”。我在 Visual Studio 中制作了一个客户端程序，但是当我收到包时，消息末尾有 iiiiii ，并且包未按正确的顺序通过。我将把代码放在这里，如果您知道我缺少什么，我将非常感激。

#include <iostream>
#include <stdio.h>
#include <string.h>
#include "winsock2.h"

#define _WINSOCK_DEPRECATED_NO_WARNINGS

#pragma warning(disable:4996)
#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main()
{
    FILE* file;

    file = fopen("package.txt", "w");

    if (file == NULL) {
        printf("Error openning the file\n");
        exit(1);
    }

    int iResult;

    WSADATA wsaData;

    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != NO_ERROR)
        printf("Error WSAStartup\n");

    SOCKET ClientSocket;
    ClientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (ClientSocket == INVALID_SOCKET)
    {
        printf("Error initializing socket with the next error code: %ld\n",
            WSAGetLastError());
        WSACleanup();
        return 0;
    }

    int Port = 13000;
    char IP[14] = "192.168.0.105";
    sockaddr_in ServerAddr;
    int AddrLen = sizeof(ServerAddr);
    ServerAddr.sin_family = AF_INET;
    ServerAddr.sin_addr.s_addr = inet_addr(IP);
    ServerAddr.sin_port = htons(Port);

    if (connect(ClientSocket, (SOCKADDR*)&ServerAddr, AddrLen) == SOCKET_ERROR)
    {
        printf("Error connecting with the next error code: %ld\n",
            WSAGetLastError());
        WSACleanup();
        return 0;
    }
    else {
        printf("Sikeres kapcsolodas\n");
    }

    char message[15];
    int receiving = 0;
    while (receiving != SOCKET_ERROR) {
        receiving = recv(ClientSocket, message, sizeof(message), 0);
        fprintf(file, "%s\n", message);
        printf("%i, %i\n", receiving, sizeof(message));
    }
    
    if (receiving == SOCKET_ERROR) {
        printf("Error at receiving the message\n");
        closesocket(ClientSocket);
        WSACleanup();
        return 0;
    }

    fclose(file);

    return 0;
}

我收到的消息如下所示：

0.00/176.00ÌÌÌÌÌÌÌÌÌÌÌÌ 0.75/180.003.75ÌÌÌÌÌÌÌÌ /179.008.63/179ÌÌÌÌÌÌÌÌ .009.008.63/179ÌÌÌÌÌÌÌÌ 14.06/179.0019.ÌÌÌÌÌÌÌÌ 13/178.00.0019.ÌÌÌÌÌÌÌÌ 24.19/178.0019.ÌÌÌÌÌÌÌÌ 29.44/179.0019.ÌÌÌÌÌÌÌÌ 35.06/178.0019.ÌÌÌÌÌÌÌÌ 39.94/180.0045.ÌÌÌÌÌÌÌÌ 19/178.00.0045.ÌÌÌÌÌÌÌÌ 50.44/180.0045.ÌÌÌÌÌÌÌÌ 55.69/179.0061.ÌÌÌÌÌÌÌÌ 50/179.00.0061.ÌÌÌÌÌÌÌÌ 66.19/180.0072.ÌÌÌÌÌÌÌÌ 38/178.00.0072.ÌÌÌÌÌÌÌÌ 77.63/178.0083.ÌÌÌÌÌÌÌÌ 25/178.00.0083.ÌÌÌÌÌÌÌÌ 88.13/178.0093.ÌÌÌÌÌÌÌÌ 56/176.00.0093.ÌÌÌÌÌÌÌÌ 99.19/177.0093.ÌÌÌÌÌÌÌÌ 104.44/177.0011 ÌÌÌÌÌÌÌÌ 0.25/176.000011 ÌÌÌÌÌÌÌÌ 115.31/177.0011 ÌÌÌÌÌÌÌÌ 121.13/177.0011 ÌÌÌÌÌÌÌÌ 126.75/173.0013ÌÌÌÌÌÌÌÌ 2.19/176.00136.ÌÌÌÌÌÌÌÌ 88/176.0000136.ÌÌÌÌÌÌÌÌ 142.69/176.0014ÌÌÌÌÌÌÌÌ 8.31/177.000014ÌÌÌÌÌÌÌÌ 153.75/177.0014ÌÌÌÌÌÌÌÌ 159.38/174.0016ÌÌÌÌÌÌÌÌ 5.38/173.000016ÌÌÌÌÌÌÌÌ 170.63/174.0017ÌÌÌÌÌÌÌÌ 5.88/169.000017ÌÌÌÌÌÌÌÌ 181.13/169.0018ÌÌÌÌÌÌÌÌ 7.13/169.000018ÌÌÌÌÌÌÌÌ 192.56/167.0019ÌÌÌÌÌÌÌÌ 8.38/170.000019ÌÌÌÌÌÌÌÌ 203.81/168.0019ÌÌÌÌÌÌÌÌ 209.25/166.0021 ÌÌÌÌÌÌÌÌ 4.88/165.000021 ÌÌÌÌÌÌÌÌ 220.69/168.0021 ÌÌÌÌÌÌÌÌ 226.13/167.0023ÌÌÌÌÌÌÌÌ 1.94/167.000023ÌÌÌÌÌÌÌÌ 237.56/167.0024ÌÌÌÌÌÌÌÌ 3.38/166.000024ÌÌÌÌÌÌÌÌ 248.81/169.0025ÌÌÌÌÌÌÌÌ 4.25/169.00259.ÌÌÌÌÌÌÌÌ 88/170.00265.69ÌÌÌÌÌÌÌÌ /170.00271.31/1ÌÌÌÌÌÌÌÌ 69.0000271.31/1ÌÌÌÌÌÌÌÌ 277.50/170.0028ÌÌÌÌÌÌÌÌÌ

注意：它应该看起来像前。 241.00/32.00，位置以度数表示，距离以毫米表示。

Answer 1

在此行中：

receiving = recv(ClientSocket, message, sizeof(message), 0);

接收设置为实际收到的字节数。
它不一定是您传递的缓冲区的大小（在您的情况下，少了几个字节）。

但是，当您将文件转储到此行中：

fprintf(file, "%s\n", message);

您忽略接收到的字节数。
使用fprintf与“％s”使用零终止字符数组，resv不会添加零终止。

您可以通过在fprintf之前添加此行来解决此问题：

message[receiving] = '\0';

另一个问题是允许填充字节的最大数量recv。
由于我们要保留一个字节以零终止，因此呼叫recv应该是：

receiving = recv(ClientSocket, message, sizeof(message)-1, 0);

IE允许接收填充sizeof（message）-1 bytes，并保留一个零终止。