linux c 结构体的定义和结构体长度

struct 的定义和使用
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/*************************************************************************
    > File Name: 5-3.c
    > Author: sheepbao
    > Mail: [e-mail]
    > Created Time: 2015年07月23日 星期四 15时34分01秒
 ************************************************************************/

#include<stdio.h>
#include<string.h>
int main()
{
    struct student  //define struct name
    {    // struct member
        int number ;
        char name[20];
        char sex;
        int age;
        char addr[30];

    };
    //define struct var
    struct student s[3]={ { 10000,"zhangsan",'m',10,"china"},{10001,"lisi",'w',3,"us"} };
        s[2].number=1002;
        s[2].sex='m';
        s[2].age=23;
        strcpy(s[2].name,"haha");
        strcpy(s[2].addr,"xianshi");
        int i;
        for (i=0;i<3;i++)
        {
            printf("%d,%s,%c,%d,%s\n",s[i].number,s[i].name,s[i].sex,s[i].age,s[i].addr);

        }
    struct student *p;

    for (p=s;p<s+3;p++)
            printf("%d,%s,%c,%d,%s\n",p->number,p->name,p->sex,p->age,p->addr);
        return 0;


}

结构体的长度用sizeof求，其长度和边界对齐有关系

#include<stdio.h>

int main()
{
    struct data
    {
        long        l;
        char        *s;
        short int    i;
        char        c;
        short int    a[5];
    }d;

    struct data *p = &d;

    printf("%d\n",sizeof(d));
    printf("%x\t%x\n",p,p+1);
    printf("%x\t%x\n",p,(char *)p+1);
    printf("%x\t%x\n",p,(long *)p+1);

    return 0;
}