auto item = val1 + val2; // 由val1和val2相加的结果推断出item的类型
auto i=0, *p = &i; // i是整数，p是整型指针

auto sz = 0, pi = 3.14; // Error!

int count = 10;
int& countRef = count;
auto myAuto = countRef;

countRef = 11;
cout << count << " "; // print 11

myAuto = 12;
cout << count << endl; // print 11

int i = 0;
const int ci = i, &cr = ci;
auto b = ci; // b 是一个整数（ci的顶层const特性被忽略掉）
auto c = cr; // c 是一个整数（cr是ci的别名，ci本身是一个顶层const）
auto d = &i; // d 是一个整型指针（整数的地址就是指向整数的指针）
auto e = &ci; // e 是一个指向整数常量的指针（对常量对象取地址是一种底层const）

const auto f = ci; // ci 的推演类型是int，f是const int类型

auto &g = ci; // g是一个整型常量引用，绑定到ci
auto &h = 42; // Error: 不能为非常量引用绑定字面值
const auto &j = 42; // OK: 可以为常量引用绑定字面值

auto k = ci, &l = i; // k是整数，l是整型引用
auto &m = ci, *p = &ci; // m是对整型常量的引用，p是指向整型常量的指针
auto &n = i, *p2 = &ci; // Error: i的类型是int，而&ci的类型是const int

int j = 0; // Variable j is explicitly type int.
auto k = 0; // Variable k is implicitly type int because 0 is an integer.

map<int,list<string>>::iterator i = m.begin(); 
auto i = m.begin(); 

#include <deque>
using namespace std;

int main()
{
  deque<double> dqDoubleData(10, 0.1);

  for (auto iter = dqDoubleData.begin(); iter != dqDoubleData.end(); ++iter)
  { /* ... */ }

  // prefer range-for loops with the following information in mind
  // (this applies to any range-for with auto, not just deque)

  for (auto elem : dqDoubleData) // COPIES elements, not much better than the previous examples
  { /* ... */ }

  for (auto& elem : dqDoubleData) // observes and/or modifies elements IN-PLACE
  { /* ... */ }

  for (const auto& elem : dqDoubleData) // observes elements IN-PLACE
  { /* ... */ }
}

double x = 12.34;
auto *y = new auto(x), **z = new auto(&x);

auto x = 1, *y = &x, **z = &y; // Resolves to int.
auto a(2.01), *b (&a);     // Resolves to double.
auto c = 'a', *d(&c);     // Resolves to char.
auto m = 1, &n = m;      // Resolves to int.

int v1 = 100, v2 = 200;
auto x = v1 > v2 ? v1 : v2;

int f(int x) { return x; }
int main()
{
  auto x = f(0);
  const auto & y = f(1);
  int (*p)(int x);
  p = f;
  auto fp = p;
  //...
}