指針引用與引用

  感覺指針和引用之間的奇妙，寫了兩端代碼以搞清楚指針引用和引用的用法

讀C＋＋primer 一書

感覺指針和引用之間的奇妙，寫了兩端代碼以搞清楚指針引用和引用的用法

#include <iostream>

using namespace std;

int main(void)
{
 int  ival1 = 1024 ;
 int *pival1 = &ival1;   //ival的指針
 int *& pi1 = pival1;   //ival的指針的引用
   
 int  ival2 = 2048;
 int *pival2 = &ival2;   //iva2的指針
 int *& pi2 = pival2;   //iva2的指針的引用

 cout<<"ival1: "<<ival1<<endl;
 cout<<"pival1:"<<pival1<<endl;
 cout<<"pi1:   "<<pi1<<endl;
 cout<<"ival2: "<<ival2<<endl;
 cout<<"pival2:"<<pival2<<endl;
 cout<<"pi2:   "<<pi2<<endl;
  
 cout<<"-------------------"<<endl;

 *pi1 = *pi2;    //解除指針引用
 
 cout<<"ival1: "<<ival1<<endl;
 cout<<"pival1:"<<pival1<<endl;
 cout<<"pi1:   "<<pi1<<endl;
 cout<<"ival2: "<<ival2<<endl;
 cout<<"pival2:"<<pival2<<endl;
 cout<<"pi2:   "<<pi2<<endl;
 
 /*out put
 ival1: 1024
 pival1:0xbfffe6a4
 pi1:   0xbfffe6a4
 ival2: 2048
 pival2:0xbfffe698
 pi2:   0xbfffe698
 -------------------
 ival1: 2048
 pival1:0xbfffe6a4
 pi1:   0xbfffe6a4
 ival2: 2048
 pival2:0xbfffe698
 pi2:   0xbfffe698
   
 */
 //輸出說明*pi1 = *pi2;
 //之間的賦值并未改變指針引用的值，即地址的值
 //而是改變了引用對象的值
}

///////////////////////////////////////////////////////////////////////////////////

#include <iostream>

using namespace std;

int main(void)
{
 int  ival1 = 1024 ;
 int *pival1 = &ival1;
 int *& pi1 = pival1;
   
 int  ival2 = 2048;
 int *pival2 = &ival2;
 int *& pi2 = pival2;

 cout<<"ival1: "<<ival1<<endl;
 cout<<"pival1:"<<pival1<<endl;
 cout<<"pi1:   "<<pi1<<endl;
 cout<<"ival2: "<<ival2<<endl;
 cout<<"pival2:"<<pival2<<endl;
 cout<<"pi2:   "<<pi2<<endl;
  
 cout<<"-------------------"<<endl;
   
 pi1 = pi2;
 cout<<"ival1: "<<ival1<<endl;
 cout<<"pival1:"<<pival1<<endl;
 cout<<"pi1:   "<<pi1<<endl;
 cout<<"*pi1:  "<<*pi1<<endl;
 
 cout<<"ival2: "<<ival2<<endl;
 cout<<"pival2:"<<pival2<<endl;
 cout<<"pi2:   "<<pi2<<endl;
 cout<<"*pi2:  "<<*pi2<<endl;       
 
 /*out put
 ival1: 1024
 pival1:0xbffff5a4
 pi1:   0xbffff5a4
 ival2: 2048
 pival2:0xbffff598
 pi2:   0xbffff598
 -------------------
 ival1: 1024
 pival1:0xbffff598
 pi1:   0xbffff598
 *pi1:  2048
 ival2: 2048
 pival2:0xbffff598
 pi2:   0xbffff598
 *pi2:  2048
 */  
 //輸出說明，指針引用之間的賦值只改變指針的值
 //引用對象的值沒有改變
}