1. Compiler Specific: Visual C++
    

   
   #include <sys\types.h>
   #include <sys\stat.h>
   __int64 FileSize64( const char * szFileName ) 
   { 
     struct __stat64 fileStat; 
     int err = _stat64( szFileName, &fileStat ); 
     if (0 != err) return 0; 
     return fileStat.st_size; 
   }

2. Non-Portable Version: stat()

    

   
   #include <sys\types.h>
   #include <sys\stat.h> 
   int FileSize( const char * szFileName ) 
   { 
     struct stat fileStat; 
     int err = stat( szFileName, &fileStat ); 
     if (0 != err) return 0; 
     return fileStat.st_size; 
   }

3. Portable Version: ifstream::tellg()

   
   

   
   #include <fstream>
   int FileSize(const char* sFileName)
   {
     std::ifstream f;
     f.open(sFileName, std::ios_base::binary | std::ios_base::in);
     if (!f.good() || f.eof() || !f.is_open()) { return 0; }
     f.seekg(0, std::ios_base::beg);
     std::ifstream::pos_type begin_pos = f.tellg();
     f.seekg(0, std::ios_base::end);
     return static_cast<int>(f.tellg() - begin_pos);
   }

4. Using Boost

    

   
   #include <boost/filesystem/operations.hpp>
   boost::intmax_t file_size( const path & ph );
   

 

參考：

Quick and Dirty Series: C++ FileSize() function