Synchronizing with atomics

I’ve been reading and learning about the C++ memory model and relaxed atomics and decided to rewrite my Interview question, part 1 using

atomic<bool>

‘s to synchronize the threads. I took it one step further and created three threads that print A, B, C, A, B, C,…
Each thread waits for its

atomic<bool>

to be set to true while spinning; prints then sets the next thread’s flag. The wait is a CAS (compare-and-swap) operation.
Next, I will try to figure out how to relax the

compare_exchange

and the

store

calls with

memory_order_acquire

and

memory_order_release

parameters 🙂

Complete listing:

#include 
#include 
#include 
using namespace std;

const int COUNT = 3;

int main(int argc, char** argv)
{
	atomic e1{false}, e2{false}, e3{false};
	
	thread t1([&](){
		for(int i = 0; i < COUNT; ++i)
		{
			bool e = true;
			while(!e1.compare_exchange_strong(e, false)) e = true;
			cout << "A" << endl;
			e2.store(true);
		}
	});
	
	thread t2([&](){
		for(int i = 0; i < COUNT; ++i)
		{
			bool e = true;
			while(!e2.compare_exchange_strong(e, false)) e = true;
			cout << "B" << endl;
			e3.store(true);
		}
	});
	
	thread t3([&](){
		for(int i = 0; i < COUNT; ++i)
		{
			bool e = true;
			while(!e3.compare_exchange_strong(e, false)) e = true;
			cout << "C" << endl;
			e1.store(true);
		}
	});
	
	e1.store(true);
	
	t1.join();
	t2.join();
	t3.join();
	
	return 1;
}

A
B
C
A
B
C
A
B
C
Program ended with exit code: 1

Program output.