using namespace std;

​

union ShareData

{

    unsigned char a;

    unsigned short b;

    unsigned int c;

};

​

int main(void)

{

    ShareData var;

    var.c = 0x12345678;

    cout << hex;

    cout << var.a << endl;

    cout << var.b << endl;

    cout << var.c;

    return 0;

}