C++万能头文件

Hello，大家好！

又见面了，���们一起来了解一下C++的万能头文件吧

我们在写c++程序时是否遇到过因为没有导入库文件而导致报错，或者多次导入库文件时导致重复导入？这时我们就可以使用万能头文件来解决需要写很多头文件的麻烦

首先，万能头文件是怎么写的可不能写错

#include

优点：

封装了c+标准库中几乎所有的头文件，引入之后就可以使用c++ 所有的头文件中的功能；

缺点：

1、并不是所有编译器都支持万能头文件的编译（比如说visual stido)

           2、 限制了程序可移植性

           3、由于在该头文件中包含了c++所有的头文件，在程序编写的过程中，程序中的变量

                 函数可能会和c++标准库中的命名冲突。

所以，在大型项目中尽量不要使用万能头文件！！！

万能头文件在DEV-C++中的定义是这样的（编程初学者都建议看一下）：

// C++ includes used for precompiling -*- C++ -*-// Copyright (C) 2003-2020 Free Software Foundation, Inc.//// This file is part of the GNU ISO C++ Library.  This library is free// software; you can redistribute it and/or modify it under the// terms of the GNU General Public License as published by the// Free Software Foundation; either version 3, or (at your option)// any later version.// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU General Public License for more details.// Under Section 7 of GPL version 3, you are granted additional// permissions described in the GCC Runtime Library Exception, version// 3.1, as published by the Free Software Foundation.// You should have received a copy of the GNU General Public License and// a copy of the GCC Runtime Library Exception along with this program;// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see// ./** @file stdc++.h *  This is an implementation file for a precompiled header. */// 17.4.1.2 Headers// C#ifndef _GLIBCXX_NO_ASSERT#include #endif#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if __cplusplus >= 201103L#include #include #include #include #include #include #include #include #endif// C++#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if __cplusplus >= 201103L#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #endif#if __cplusplus >= 201402L#include #endif#if __cplusplus >= 201703L#include #include // #include #include #include #include #include #include #endif#if __cplusplus > 201703L#include #include #include #include #include #include #include // #include #include #endif

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