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053第十章 结构体与共用体01(新版)

发布时间：2021-05-06 15:16:41编辑：雪饮阅读（）

 看圖下定義


首先定义一个结构date，由month(月)、day(日)、year(年) 三个成员组成。
 
在定义并说明变量 boy1 和 boy2 时，其中的成员birthday被说明为data结构类型。成员名可与程序中其它变量同名，互不干扰。
實現
#include <stdio.h>
void main()
{
      struct date           
      {         
            int month;           
            int day;           
            int year;           
      };
     
      struct
      {           
            int num;           
            char name[20];           
            char sex;           
            struct date birthday;           
            float score;            
      } boy1, boy2;
     
     
      printf("Please input birthday(YY:) ");
      scanf("%d", &boy1.birthday.year);
      printf("Please input birthday(MM:) ");
      scanf("%d", &boy1.birthday.month);
      printf("Please input birthday(DD:) ");
      scanf("%d", &boy1.birthday.day);
      printf("\n");
 
      boy2 = boy1;
 
      printf("boy1's birthday is %d-%d-%d\n", boy1.birthday.year, boy1.birthday.month, boy1.birthday.day);
      printf("boy2's birthday is %d-%d-%d\n", boy2.birthday.year, boy2.birthday.month, boy2.birthday.day);
}
D:\cproject>gcc main.c -o m
 
D:\cproject>m.exe
Please input birthday(YY:) 1992
Please input birthday(MM:) 02
Please input birthday(DD:) 04
 
boy1's birthday is 1992-2-4
boy2's birthday is 1992-2-4
結構躰是一個複合數據類型
這在上面的示例中可以體現出來，可以在看看下面這個實例
#include <stdio.h>
 
void main()
{
      struct student
      {
            int num;
            char *name;
            char sex;
            float score;
      } boy1, boy2;
     
      boy1.num = 007;
      boy1.name = "Jane";
     
      printf("Please input sex and score\n");
      scanf("%c %f", &boy1.sex, &boy1.score);
     
      boy2 = boy1;
 
      printf("Number = %d\nName = %s\n", boy2.num, boy2.name);
      printf("Sex = %c\nScore = %f\n", boy2.sex, boy2.score);
      
}
D:\cproject>m.exe
Please input sex and score
g 23
Number = 7
Name = Jane
Sex = g
Score = 23.000000
結構體變量的引用
可以引用结构体变量成员的地址，也可以引用结构体变量的地址
實例如：
#include <stdio.h>
 
void main()
{
      struct student
      {
            int num;
            char *name;
            char sex;
            float score;
      } boy1;
     
      boy1.num = 007;
      boy1.name = "Jane";
      /*
        %0 无符号以八进制表示的整数
        */
      printf("The address of struct is %o :\n", &boy1 );
      printf("The address of num is %o :\n", &boy1.num );
        
        printf("The address of struct is(16) %p :\n", &boy1 );
      printf("The address of num is(16) %p :\n", &boy1.num );
 
}
D:\cproject>gcc main.c -o m
 
D:\cproject>m.exe
The address of struct is 30377000 :
The address of num is 30377000 :
The address of struct is(16) 000000000061FE00 :
The address of num is(16) 000000000061FE00 :
有一個疑問，爲什麽結構躰地址用8進制輸出？一般地址不都是用16進制輸出的嗎？
只是例子而已？沒有意義？
谁说没有意义的，linux、unix中很常见啊,windows中八进制和十六进制也不少
或者说八进制和十六进制的好处是熟练者可以一眼看出相关含义，比如unix、linux中的文件属性（八进制），硬件相关的字节、地址什么的。