Question

我的代码设置std :: failbit到达eof并抛出异常我怎么能跳过eof异常

在catch块中我检查并跳过，如果异常是因为eof但它不好。

请建议我如何在以下代码中跳过eof异常

std::ifstream in
std::string strRead;
in.exceptions ( std::ifstream::failbit | std::ifstream::badbit );
try
{

while (getline( in,strRead))

{
         //reading the file
 }

 catch(std::ifstream::failure & exce)
{
         if(! in.eof())   // skip if exception because of eof but its not working?
        {
               cout<<exce.what()<<endl;
                return false;
        }


}
catch(...)
{

        cout("Unknow  exception ");
        return false;
}

Answer 1

当使用（使用getline（））时，每次获得此异常时，禁用failbit将是最好的方法

Answer 2

在私下讨论之后，我们设法找到了解决问题的方法：getline(in, strRead)会在达到eof时将failbit设置为1（正常行为）并且他不希望这种情况发生。我们同意使用其他方法来读取文件的内容：

std::ifstream in(*filename*); // replace *filename* with actual file name.
// Check if file opened successfully.
if(!in.is_open()) {
       std::cout<<"could not open file"<<std::endl;
       return false;
}

in.seekg(0, std::ios::end);
std::string strRead;

// Allocate space for file content.
try {
    strRead.reserve(static_cast<unsigned>(in.tellg()));
} catch( const std::length_error &le) {
    std::cout<<"could not reserve space for file"<<le.what()<<std::endl;
    return false;
} catch(const std::bad_alloc &bae) {
    std::cout<<"bad alloc occurred for file content"<<bae.what()<<std::endl;
    return false;
} catch(...) {
    std::cout<<"other exception occurred while reserving space for file content"<<std::endl;
    return false;
}

in.seekg(0, std::ios::beg);
// Put the content in strRead.
strRead.assign(std::istreambuf_iterator<char>(in),
        std::istreambuf_iterator<char>());
// Check for errors during reading.
if(in.bad()) {
    std::cout<<"error while reading file"<<std::endl;
    return false;
}

return true;

虽然在catch块中处理了正确的eof后，我的代码提升了basic_ios :: clear。

2 个答案: