Tag: C

C’s secret operator: goes to

krzaq 2 Comments

Consider the following code:

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#include <iostream>
 
using namespace std;
 
int main()
{
	int n = 10;
 
	while(n --> 0)
		cout << "n: " << n << endl;
}

Should it compile? If your answer is yes, what should be its output?

So I was cold last night…

krzaq Leave a comment 
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#include <atomic>
#include <chrono>
#include <iomanip>
#include <iostream>
#include <string>
#include <thread>
#include <vector>
 
using namespace std;
 
int main()
{
	auto known_cores = thread::hardware_concurrency();
	auto cores = max(known_cores-1,decltype(known_cores){1});
 
	volatile bool done = false;
 
	auto f = [&](){	while(!done); };
 
	vector<thread> v;
	for(decltype(cores) i{0}; i < cores-1; ++i){
		v.push_back(thread{f});
	}
 
	string temp;
	getline(cin,temp);
 
	done = true;
 
	for(auto&& t : v){
		t.join();
	}
 
	return 0;
}

Proper C, improper C++

krzaq 5 Comments

I have recently been asked if it’s possible to write a legit C program that wouldn’t compile in C++ mode. Obviously, my answer was positive, but the question made me wonder just how many incompatibilities there are between these languages, and how many of these I can cram into a single test case? I’ve decided to try my hand at writing such test case, and after a while of research I ended up with a fairly decent attempt.