#include <iostream>
#include <cstdlib>
using namespace std;
int main()
{
   char ch='z';
   char ch_arr[10]="abcd";
   char *pch;
   int a=10, b=20;
   int *p1, *p2;
   int sub1, sub2;
   float c=30.0;
   float *ptrf;
   /* 設定運算 */
   p1 = &a;   /* 將a的位址存放於p1 */
   p2 = &b;   /* 將b的位址存放於p2 */
   pch = &ch; /* 將ch的位址存放於pch */
   ptrf = &c;
   
   cout << "addr. of a、p1 : " << p1 << " 、 " << &p1 << endl;
   cout << "sizeof(a) : " << sizeof(a) << endl;
   cout << "sizeof(p1) : " << sizeof(p1) << endl;
   cout << "sizeof(*p1) : " << sizeof(*p1) << endl << endl;   

   cout << "addr. of b、p2 : " << p2 << " 、 " << &p2 << endl;
   cout << "sizeof(b) : " << sizeof(b) << endl;
   cout << "sizeof(p2) : " << sizeof(p2) << endl << endl;

   cout << "addr. of c、ptrf : " << ptrf << " 、 " << &ptrf << endl;
   cout << "sizeof(c) : " << sizeof(c) << endl;
   cout << "sizeof(ptrf) : " << sizeof(ptrf) << endl << endl;
//這行的字元變數位址取不到 
   cout << "addr. of ch、pch: " << &ch << " 、 " << &pch << endl;   
   cout << "sizeof(ch) : " << sizeof(ch) << endl;
   cout << "sizeof(pch) : " << sizeof(pch) << endl << endl;

   cout << "addr. of ch_arr : " << &ch_arr << endl;
   cout << "addr. of ch_arr + 1 : " << *ch_arr+1 << endl;
   cout << "addr. of ch_arr + 2 : " << *ch_arr+2 << endl;
   /* 差值運算*/
   sub1 = p1 - p2;    /* 計算p1和p2相差距離 */
   sub2 = *p1 - *p2;  /* 計算p1所指變數a和p2所指變數b的差 */
   
   cout << endl << "=======================" << endl;
   cout << "sub1 = " << sub1 << endl;
   cout << "sub2 = " << sub2 << endl;
 
   cout << endl << "=======================" << endl; 
   cout << "Before process ... " << endl;
   cout << "addr. of p1 : " << p1 << endl;
   cout << "addr. of p2 : " << p2 << endl; 
//這行的字元變數位址取不到 
   cout << "addr. of pch : " << pch << endl;        
   /* 加減法運算 */
   p1++;   /* 將p1所存整數a位址加上整數型態長度4bytes */
   p2--;   /* 將p2所存整數b位址減去整數型態長度4bytes */   
   pch++;  /* 將pch所存字元ch位址加上字元型態長度1byte */
   
   cout << endl << "=======================" << endl; 
   cout << "After process ... " << endl;
   cout << "addr. of p1 : " << p1 << endl;
   cout << "addr. of p2 : " << p2 << endl;
//這行的字元變數位址取不到 
   cout << "addr. of pch : " << pch << endl;   
 
   system("pause");
   return 0;
}