數據成員是reference或const時該如何賦值？

#include <string>
#include <iostream>

class Dog
{
public:
    // 成員是reference或const時必須在初始化列表中進行賦值
    Dog(std::string &name, int &age) : m_name(name), m_age(age){
        std::cout << "Dog ctor called." << std::endl;
    }
    const std::string & getName() {
        return m_name;
    }
    int getAge() {
        return m_age;
    }
protected:
private:
    std::string &m_name;
    const int m_age;
};

int main()
{
    std::string name("huabao");
    int age(5);
    Dog adog(name,age);
    name = "xinba";
    std::cout << adog.getName() << std::endl;  // 5
    /* 類成員m_name是name的引用 */
    std::cout << adog.getAge() << std::endl;   // xinba

    return 0;
}