Vicfred Vicfred

Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.

There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.

1. Combined type and variable/field declaration, inside a struct scope [https://godbolt.org/g/Rh94Go]

struct foo {
   struct bar {
 int x;

	#include <cstdio>
	#include <cstdlib>
	#include <cstring>
	#include <algorithm>
	#include <functional>

	#define MAXN 1001

	using namespace std;

	//http://www.codechef.com/problems/COLARR/
	#include <cstdio>
	#include <cstdlib>
	#include <cstring>
	#include <algorithm>

	#define MAXN 1005

	using namespace std;

	//http://www.codechef.com/problems/MARBLEGF/
	#include <iostream>
	#include <cstdio>
	#include <cstring>
	#include <cstdlib>
	#include <cctype>
	#include <algorithm>
	#include <map>
	#include <vector>
	#include <list>

	//https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1572
	#include <cstdio>
	#include <cstdlib>

	using namespace std;

	int gcd(int a, int b) { return b == 0 ? a : gcd(b, a%b); }

	int main() {

	//http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=2498
	#include <iostream>
	#include <cstdio>
	#include <cstring>
	#include <cstdlib>
	#include <cctype>
	#include <algorithm>
	#include <map>
	#include <vector>
	#include <list>

	//http://www.spoj.com/OI/problems/DMAYA/
	#include <cstdio>
	#include <cstdlib>
	#include <cstring>
	#include <queue>

	using namespace std;

	int main () {
	int g, sz;

	// How many times do you have to flip a coin
	// to get n heads?
	#include <random>
	#include <iostream>

	int main() {
	std::random_device rd;
	std::mt19937 gen(rd());
	std::uniform_int_distribution<> dis(0,1);

	// approximate pi using random points in a square
	// compile using: g++ pi.cpp -o pi
	// and then run using: ./pi
	#include <iostream>
	#include <iomanip>
	#include <random>
	#include <cmath>
	#include <chrono>

	using namespace std;

	#include <vector>
	#include <bitset>
	#include <iostream>
	#include <chrono>

	using namespace std;

	const int MAXN = 10000000;

	bitset<MAXN+2> bs;