C++ sizeof

 1 #include <iostream>
 2 using namespace std;
 3  
 4 #define my_sizeof(type) (char *)(&type+1)-(char*)(&type)
 5 
 6 union u
 7 {
 8     double a;
 9     int b;
10 }; 
11 
12 union u2
13 {
14     char a[13];
15     int b;
16 }; 
17 
18 union u3
19 {
20     char a[13];
21     char b;
22 }; 
23 
24 struct s4
25 {
26     int i: 8;
27     int j: 4;
28     int a:3;
29     double b;
30 }; 
31 
32 int main()
33 {
34     double x;
35     string s("hello world");
36     cout << my_sizeof(x) << endl;
37     cout << sizeof(s) << endl;
38 
39     char a[] = "abcdef";
40     cout << sizeof(a) << endl;
41 
42     int b[20] = {3, 4};
43     cout << sizeof(b) << endl;
44 
45     char c[2][3] = {"aa", "bb"};
46     cout << sizeof(c) << endl;
47 
48     cout << sizeof(u) << endl; // 8
49     cout << sizeof(u2) << endl; // 16
50     cout << sizeof(u3) << endl; // 13
51 
52     cout << sizeof(s4) << endl;
53     getchar();
54     return 0;
55 }