#include <iostream>

struct A{
    int a;
    unsigned b:16; // for demonstration purpose only
    bool c:1;
};

int main()
{
   std::cout<<"sizeof(A) is "<<sizeof(A)<<std::endl;
}

#include <iostream>

struct A{
	int a;
	union{
		int dummy;
		struct{
		    unsigned v1:16;
		    bool     v2:1;
		};
	};
};


int main()
{
	A a;
	a.v2 = true;
	a.dummy = 0;
   
	std::cout<<"a.v2 is "<<a.v2<<std::endl;
}