#pragma pack(1)
struct S1 {
    unsigned char a0: 1;
    unsigned char a1: 1;
    unsigned char a2: 1;
    unsigned char a3: 1;
    unsigned char a5: 1;
    unsigned short a6: 11;
};

struct S2 {
    unsigned short a0: 1;
    unsigned short a1: 1;
    unsigned short a2: 1;
    unsigned short a3: 1;
    unsigned short a4: 1;
    unsigned short a6: 11;
};

int main(int argc, char* argv[])
{
    printf("sizeof S1 %d\n", sizeof(struct S1));
    printf("sizeof S2 %d\n", sizeof(struct S2));
    return 0;
}