#include<iostream>
using namespace std;

int main(){
    int i = 0, & r = i;
    auto a = r;//int a =r;是可以修改a 的 值的.
    const int ci = i, & cr = ci;
    auto b = ci;//相当于 int b = ci;
    auto c = cr;//int c =cr;
    auto d = &i;//相当于int *d =i 也就是d指向了i,所以d=42相当于 int *d =42.是不可以的.指针只能指向对象
    auto e = &ci;//也是个指针
    const auto f = ci;
    auto& g = ci;//g是个引用,引用会保留顶层const.所以g不能改变,因为不能给常量赋值
    const auto& j = 42;
    cout << a << " "<<d <<endl;
    d = 42;
    cout<<a<<" "<<d<< endl;

    return 0;
}