结构体按最长的数据类型对齐,所占内存的大小为结构体的所占内存最大的成员数据类型的整数倍。而各种数据类型的指针,所占的内存是4字节。示例如下:
#include<iostream> using namespace std; typedef struct t { bool a; int b; bool c; struct t*next; }; struct t1 { bool a; short b; bool c; }; struct t2 { bool a; char b; bool c; }; int main() { cout << "sizeof(t) "<<sizeof(t) << endl <<"sizeof(t1) "<< sizeof(t1) << endl <<"sizeof(t2) "<< sizeof(t2) << endl; cout<<"int "<<sizeof(int)<<endl<<"bool "<<sizeof(bool)<<endl<<"short "<<sizeof(short)<<endl<<"char "<<sizeof(char)<<endl; struct t *tttt; cout<<"tttt "<<sizeof(tttt)<<endl; char **a[3][4]; cout<<"sizeof(a) "<<sizeof((a))<<" sizeof(&a)"<<sizeof (&a)<<endl;//&a大小是4 double *p; cout<<"sizeof(*double) "<<sizeof(p)<<endl;//大小是4 int *q; cout<<"sizeof(*int) "<<sizeof(q)<<endl; //大小是4 char *s; cout<<"sizeof(*char) "<<sizeof(s)<<endl; char b[10]; cout<<"sizeof(b) "<<sizeof(b)<<endl; char *c[10]; cout<<"sizeof(c) "<<sizeof(c)<<" sizeof(*c) "<<sizeof(*c)<<" sizeof(&c) "<<sizeof(&c)<<endl; int x; int *r=&x; int **rr=&r; cout<<"sizeof(rr) "<<sizeof(rr)<<endl;//大小是4 ,rr是二级指针,是指向指针的指针,本质是还是指针。 system("pause"); }