【004：结构体内存地址的连续问题】

代码如下，编辑器是为mingw32

/**
********************************************************
测试:关于结构体内存对齐和内存地址连续的问题
***********************************************************
*/


#include <stdio.h>



#pragma pack(push)
#pragma pack(1)
typedef struct _GPIO{
    int num;
    char ch;
    char hj;
    int key;
}GPIO;
#pragma pack(pop)

typedef struct _USART{
    int num;
    char ch;
    char hj;
    int key;
}USART;





int main(void)
{
    GPIO gpio;
    USART usart;
    printf("内存对齐的简单测试 \n");
    printf("\r\n sizeof(int) = %d ",sizeof(int));
    printf("\r\n sizeof(char) = %d ",sizeof(char));
    printf("\r\n sizeof(gpio) = %d ",sizeof(gpio));
    printf("\r\n sizeof(usart) = %d ",sizeof(usart));

    printf("内存连续的简单测试 \n");
    printf("\r\n gpio  0X%04X  0X%04X  0X%04X  0X%04X",&gpio.num,&gpio.ch,&gpio.hj,&gpio.key);
    printf("\r\n usart 0X%04X  0X%04X  0X%04X  0X%04X",&usart.num,&usart.ch,&usart.hj,&usart.key);



    return 0;
}

输出结果如下

 内存对齐的简单测试

 sizeof(int) = 4
 sizeof(char) = 1
 sizeof(gpio) = 10
 sizeof(usart) = 12

 内存连续的简单测试

 gpio  0X60FEA6  0X60FEAA  0X60FEAB  0X60FEAC
 usart 0X60FE98  0X60FE9C  0X60FE9D  0X60FEA0

分析结果如下

• struct的内存地址是连续的，与结构定义结构体变量的顺序相同；