#include<bits/stdc++.h>介绍：

最近写编程题时发现了一个神奇的头文件，#include<bits/stdc++.h>，很多人在只要引用了这个头文件之后，就无须再引用其他头文件，百度之后感觉挺有用的，写题时方便快捷（不建议经常使用，如果长期使用容易把库函数名字淡忘掉）

使用：

使用前
#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>
using namespace std;

int main(){
    return 0;
}

使用后
#include<bits/stdc++.h>
using namespace std;
int main(){
    return 0;
}

如何调用：

1. DEV C++软件可直接使用 #include <bits/stdc++.h>
2. VS不行，需先在VS中添加此头文件，方法如下

1.在安装路径下，依次进入:

VC --> Tools --> MSVC --> 14.13.26128(此文件夹名每个人会有不同) --> include

大致是这么个方向，但是要以实际情况为准

D:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.13.26128\include\bits
这是别人的

C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include
这是我的路径

如果实在找不到，建议下一个Everything，全局搜索include，然后进行一个个比对看看哪个目录中含有自己用的头文件（如最常见的stdio.h），就是这个啦

2.在 include 文件夹下新建一个 bits 文件夹，在此文件夹下添加 stdc++.h 头文件，内容就是以下代码块中的代码

// C++ includes used for precompiling -*- C++ -*-
 
// Copyright (C) 2003-2015 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
// <http://www.gnu.org/licenses/>.
 
/** @file stdc++.h
 *  This is an implementation file for a precompiled header.
 */
 
// 17.4.1.2 Headers
 
// 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 <cstdalign>
#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

3. 之后VS 就可以直接添加头文件 #include <bits/stdc++.h> 使用了。