struct大小

对齐。

 #include <iostream>
 using namespace std;

 struct S1 {
     int a;
     char b;
     char c;
 };

 struct S2 {
     int a;
     char b;
     char c;
     double d;
 };

 struct S3 {
     int a;
     char b;
     int c;
     double d;
 };

 struct S4 {
     int a;
     char b;
     int c;
     double d;
     char e[];
     static char f[];
 };
 int main(int argc, char** argv) {
     cout << "sizeof(S1): " << sizeof(S1) << endl;
     cout << "sizeof(S2): " << sizeof(S2) << endl;
     cout << "sizeof(S3): " << sizeof(S3) << endl;
     cout << "sizeof(S4): " << sizeof(S4) << endl;
     return ;
 }

输出：

 root@xxj-VirtualBox:~/interview# ./struct
 sizeof(S1):
 sizeof(S2):
 sizeof(S3):
 sizeof(S4): 

static变量是不占空间的。