#include <iostream>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

//目的：有些reference API函式，其參數是const，或其傳回值是const指標（設定一次後就不可以被改值） 
//本題練習：建立一個函式，其『參數是const指標，或其傳回值也是const指標』
const int * show1(const int *p);

int main(int argc, char** argv) 
{
	int * p1 = new int;
	*p1 = 50;
	//特別注意：接收函式傳回的指標，必須宣告const int * v1 
	const int * v1 = new int;
	cout<<"(before) p1 = "<<p1<<endl; 
	cout<<"(before) *p1 = "<<*p1<<endl;
	cout<<endl;
	
	v1 = show1(p1);
	
	cout<<"(after) p1 = "<<p1<<endl; 
	cout<<"(after) *p1 = "<<*p1<<endl;
	cout<<endl;
	cout<<"(after) v1 = "<<v1<<endl; 
	cout<<"(after) *v1 = "<<*v1<<endl;
		
	return 0;
}


////////////////////////
const int * show1(const int *p)
{
	int * r1 = new int;
	//注意：不可以設定 r1 = p（因為若是設定指標相同，因為r1是另外一個記憶體位址） 
	*r1 = *p;
	*r1 = 100;
	return r1;
	
}