http://www.cnblogs.com/Anker/p/3271773.html
http://no001.blog.51cto.com/1142339/493589
#include <stdio.h> typedef union { long i; int k[5]; char c; } DATE; struct data { int cat; DATE cow; double dog; } too; int main() { printf("%ld ", sizeof(DATE)); // 24 printf("%ld ", sizeof(too)); // 40 }