MFC：讀取整個文件緩衝

Question

我已經插手了一些代碼，但我無法正確讀取整個文件...很多垃圾被附加到輸出。我該如何解決？

// wmfParser.cpp : Defines the entry point for the console application. 
// 

#include "stdafx.h" 
#include "wmfParser.h" 
#include <cstring> 

#ifdef _DEBUG 
#define new DEBUG_NEW 
#endif 


// The one and only application object 

CWinApp theApp; 

using namespace std; 

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[]) 
{ 
    int nRetCode = 0; 

    // initialize MFC and print and error on failure 
    if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0)) 
    { 
     // TODO: change error code to suit your needs 
     _tprintf(_T("Fatal Error: MFC initialization failed\n")); 
     nRetCode = 1; 
    } 
    else 
    { 
     // TODO: code your application's behavior here. 
     CFile file; 
     CFileException exp; 
     if(!file.Open(_T("c:\\sample.txt"), CFile::modeRead, &exp)){    
      exp.ReportError(); 
      cout<<'\n';   
      cout<<"Aborting..."; 
      system("pause"); 
      return 0; 
     } 

     ULONGLONG dwLength = file.GetLength(); 
     cout<<"Length of file to read = " << dwLength << '\n'; 
     /* 
     BYTE* buffer; 
     buffer=(BYTE*)calloc(dwLength, sizeof(BYTE)); 
     file.Read(buffer, 25); 
     char* str = (char*)buffer;  
     cout<<"length of string : " << strlen(str) << '\n';  
     cout<<"string from file: " << str << '\n'; 
     */ 

     char str[100]; 

     file.Read(str, sizeof(str)); 
     cout << "Data : " << str <<'\n'; 
     file.Close(); 
     cout<<"File was closed\n"; 

     //AfxMessageBox(_T("This is a test message box")); 
     system("pause"); 
    } 
    return nRetCode; 
} 

UPDATE： 專門找指導，對於註釋掉的代碼......也想聽聽其他建議太...

Answer 1

您的字符串不是空終止。您需要初始化字符串str與memset(str,0, sizeof(str));

Answer 2

我認爲這可能是更接近你正在尋找：

/* first method */ 

    ULONGLONG dwLength = file.GetLength(); 
    cout << "Length of file to read = " << dwLength << '\n'; 

    // make room for whole file, plus null 
    BYTE *buffer = (BYTE *) malloc(dwLength + 1); 

    file.Read(buffer, dwLength); // read whole file 
    *(buffer + dwLength) = '\0'; // add null 

    cout << "length of string : " << strlen(buffer) << '\n';  
    cout << "string from file: " << buffer << '\n'; 

    free(buffer); 

    file.SeekToBegin(); // Back to the beginning 

    /* second method */ 
    char str[dwLength + 1]; 

    file.Read(str, dwLength + 1); 
    str[dwLength] = '\0'; 

    cout << "Data : " << str <<'\n'; 
    file.Close(); 

    cout << "File was closed\n";