一、什么是万能头文件C的万能头文件是1#include bits/stdc.h它是一个包含了每一个标准库的头文件。优点在算法竞赛中节约时间减少了编写所有必要头文件的工作量。缺点不是GNU C库的标准头文件在部分情况下会编译失败包含了很多不必要的东西会大大增加编译时间。二、源码⚠️ 这里去除了多余的注释并删除了cstdalign。1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586// C#ifndef _GLIBCXX_NO_ASSERT#include cassert#endif#include cctype#include cerrno#include cfloat#include ciso646#include climits#include clocale#include cmath#include csetjmp#include csignal#include cstdarg#include cstddef#include cstdio#include cstdlib#include cstring#include ctime#if __cplusplus 201103L#include ccomplex#include cfenv#include cinttypes#include cstdbool#include cstdint#include ctgmath#include cwchar#include cwctype#endif// C#include algorithm#include bitset#include complex#include deque#include exception#include fstream#include functional#include iomanip#include ios#include iosfwd#include iostream#include istream#include iterator#include limits#include list#include locale#include map#include memory#include new#include numeric#include ostream#include queue#include set#include sstream#include stack#include stdexcept#include streambuf#include string#include typeinfo#include utility#include valarray#include vector#if __cplusplus 201103L#include array#include atomic#include chrono#include condition_variable#include forward_list#include future#include initializer_list#include mutex#include random#include ratio#include regex#include scoped_allocator#include system_error#include thread#include tuple#include typeindex#include type_traits#include unordered_map#include unordered_set#endif三、编译器找不到 bits/stdc.h最简单粗暴的做法就是首先找到iostream这个头文件所在的目录进入该目录创建名为bits的文件夹再进入该文件夹创建一个名为stdc.h的文件把上述源码复制进去即可。