std::ofstream File("Cannotcreate"); if(!File.is_open()){ std::cerr << "error opening \n"; } 第一种方式同样有效吗?c++ 1个回答 0投票 带有初始化的构造函数确实会构造 std::ofstream 对象并尝试打开文件。如果任何东西破坏了流并将其置于未准备好输入/输出操作的无效状态,则会设置错误标志(ba...
从CSV文件中读取数据代码: boolspeechManager::fileIsEmpty() {//创建文件流ofstream ifs(FILENAME, ios::in);//判断文件是否打开成功if(!ifs.is_open()) { cout<<"open false"<<endl;returnfalse; }charch; ifs>>ch;if(ifs.eof()) {//文件为空cout <<"no records"<<endl; ifs.close();returnf...
C++中函数指针的用途非常广泛，例如回调函数，接口类的设计等，但函数指针始终不太灵活，它只能指向全局或...
is_open checks if the stream has an associated file (public member function) close closes the associated file (public member function) open opens a file and configures it as the associated character sequence (public member function ofstd::basic_filebuf<CharT,Traits>)...
basic_ofstream::is_open basic_ofstream::open basic_ofstream::close Non-member functions swap(std::basic_ofstream) (C++11) void close(); Closes the associated file. Effectively calls rdbuf()->close(). If an error occurs during operation, setstate(failbit) is called. Parameters (none) ...
返回底层未处理的文件设备对象 (公开成员函数) 文件操作 is_open 检查流是否有关联文件 (公开成员函数) open 打开文件,并将它与流关联 (公开成员函数) close 关闭关联文件 (公开成员函数) 非成员函数std::swap(std::basic_ofstream) (C++11) 特化std::swap 算法 (函数模板) 继承...
off>>bookname 这句出错 ofstream 是写文件流，如果你的本意是想把bookname写入off里，应该写成 off<<bookname.>>是读文件时的符号
is_open checks if the stream has an associated file (public member function) open opens a file and associates it with the stream (public member function) close closes the associated file (public member function) Non-member functions std::swap(std::basic_ofstream) ...
basic_ofstream::open basic_ofstream::close Non-member functions swap(std::basic_ofstream) (C++11) Checks if the file stream has an associated file. Effectively callsrdbuf()->is_open(). Parameters (none) Return value trueif the file stream has an associated file,falseotherwise. ...
std::ios_base::openmodemode =std::ios_base::out); (5)(since C++17) basic_ofstream(basic_ofstream&&other); (6)(since C++11) basic_ofstream(constbasic_ofstream&rhs)=delete; (7)(since C++11) Constructs new file stream. 1)Default constructor: constructs a stream that is not associated ...