const a，引用变了，为啥原来常量不变
const??，?改变，不变
#include <iostream>
#include <string>
using namespace std;
void main()
{
const int a=10;
int &b=const_cast <int&>(a); //b为a的非常引用
cout<<a<<" "<<b<<endl;
cout<<"&a "<<&a<<" &b "<<&b<<endl;//ab地址相同
b=20;
cout<<a<<" "<<b<<endl;//ab值不同
cout<<"&a "<<&a<<" &b "<<&b<<endl;
int *p=&b;
int *p1=const_cast<int*>(&a);
cout<<" p=== "<<p<<" *p=== "<<*p<<endl;
cout<<" p1=== "<<p1<<" *p1=== "<<*p1<<endl;
int const *p2=&a;
cout<<" p2=== "<<p2<<" *p2=== "<<*p2<<endl;
int c=a;
cout<<"c==="<<c<<endl;
int const *p4=&a;
cout<<"*p4 "<<*p4<<endl;
cout<<"*&a= "<<*(&a)<<endl;
}
