struct test_empty { } e; int Esize = sizeof(e); struct rtx_def { unsigned short code; long long :3; int mode : 8; long long :0; long long x :31; //long long y:31; } N = {2, 7, 1 }; int Nsize = sizeof(N); // Size = 8 struct test1 { char x:1; long long :0; } F1; int F1size = sizeof(F1); // Size = 4 struct test2 { long long x :4; } F2; int F2size = sizeof(F2); // Size = 4 struct test3 { char x:1; long long :20; } F3; int F3size = sizeof(F3); // Size = 3 struct test4 { char x:1; long long :21; short Y : 14; } F4; int F4size = sizeof(F4); // Size = 6 struct test5 { char x:1; long long :17; char Y : 1; } F5; int F5size = sizeof(F5); // Size = 3 struct test6 { char x:1; long long :42; int Y : 21; } F6; int F6size = sizeof(F6); // Size = 8 struct test { char c; char d : 3; char e: 3; int : 0; char f; char :0; long long x : 4; } M; int Msize = sizeof(M); // Size = 8 int main() { return 0; }