Question

#include <stdio.h>
#include<stdlib.h>

struct try {
    int x,*x_Ptr;
    float y,*y_Ptr;
    char q,*q_Ptr;
};  //integer, float character variables and their pointers are defined in the structures.
int main (void){

    struct try den1;
    struct try den2;
    struct try den3;

    den1.x=7;
    den2.x=8;
    den1.y=-.14;
    den2.y=23.45;
    den3.q='A';

    den1.x_Ptr=&den1.x; //pointer assignments for integer.
    den2.x_Ptr=&den2.x;

    den1.y_Ptr=&den1.y; //pointer assignments for float.
    den2.y_Ptr=&den2.y;

    den3.q_Ptr=&den3.q; //pointer assignments for character.
    system("clear");


    printf("The integer in den1:%d\nThe integer in den2:%d\nThe address of integer in den1:%p\nThe address of integer in den2:%p\nThe pointer address of integer in den1:%p\nThe pointer address of integer in den2:%p\n",den1.x,den2.x,&den1.x,&den2.x,&*den1.x_Ptr,&*den2.x_Ptr);

    printf("\n");
    printf("The float in den1:%f\nThe float in den2:%f\nThe address of float in den1:%p\nThe address of float in den2:%p\nThe pointer address of float in den1:%p\nThe pointer address of float in den2:%p\n",den1.y,den2.y,&den1.y,&den2.y,&*den1.y_Ptr,&*den2.y_Ptr);

    printf("\n");
    printf("The character in den3:%c\nThe address of character in den3:%p\nThe pointer address of character in den3:%p\n",den3.q,&den3.q,&*den3.q_Ptr);

    printf("\n");

    printf("\nThe whole address of the first struct{...\n...\n...\n...\t\t\t}den1:%p\n",&den1);
    printf("\nThe whole address of the second struct{...\n...\n...\n...\t\t\t}den2:%p\n",&den2);
    printf("\nThe whole address of the second struct{...\n...\n...\n...\t\t\t}den3:%p\n",&den3);

    return 0;
}

我意识到struct中整数之一的地址与struct的地址相同。是什么原因？

Answer 1

我意识到struct中整数之一的地址与struct的地址相同。是什么原因？

因为他们有相同的地址。

该结构占用其所有成员的组合空间。对象的地址是其第一个字节的地址。 den1.x是den1的第一个成员，因此它从den1的相同字节开始。

一张图片值一千字：

address   data
00123458  07     \ <- address of x                 \  <- address of den1
00123459  00     |                                  |
0012345a  00     | space used by x                  |
0012345b  00     /                                  | space
0012345c  58   \ <- address of x_ptr                | used
0012345d  34   |                                    | by
0012345e  12   | space used by x_ptr                | den1
0012345f  00   /                                    |
00123460  29     \ <- address of y                  |
00123461  5c     |                                  |
00123462  0f     | space used by y                  |
00123463  be     /                                  |
00123464  60   \ <- address of y_ptr                |
00123465  34   |                                    |
00123466  12   | space used by y_ptr                |
00123467  00   /                                    |
00123468  41     } address of c                     |
00123469  00   \  (c only takes 1 byte)             |
0012346a  00   | padding so that c_ptr starts       |
0012346b  00   / on a multiple of 4 bytes           |
0012346c  68     \ <- address of c_ptr              |
0012346d  34     |                                  |
0012346e  12     | space used by c_ptr              |
0012346f  00     /                                  /

c struct中的指针地址

1 个答案: