64. 类模板碰到友元函数

• 类模板碰到友元的问题以及解决

• 友元类内实现

• friend void printPerson(Person<T1, T2> &p)

• 友元类外实现
• 声明：

• friend void printPerson2<>(Person<T1, T2> &p);

• 实现：

• template<class T1,class T2>
  -void printPerson2(Person<T1, T2> &p){ 。。。}

• template<class T1,class T2>
• class Person;
• template<class T1,class T2>
• void printPerson2(Person<T1, T2> &p);

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
#include <string>

template<class T1,class T2>
class Person;

template<class T1,class T2>
void printPerson2(Person<T1, T2> &p);

template<class T1,class T2>
void printPerson3(Person<T1, T2>&p)
{
	cout << "类外实现 --- 姓名： " << p.m_Name << " 年龄： " << p.m_Age << endl;
}

template<class T1, class T2>
class Person
{
	//1、友元函数 类内实现
	friend void printPerson(Person<T1, T2> &p)
	{
		cout << "姓名： " << p.m_Name << " 年龄： " << p.m_Age << endl;
	}

	//2、友元函数 类外实现
	friend void printPerson2<>(Person<T1, T2> &p);

	
	friend void printPerson3<>(Person<T1, T2> &p);
public:
	Person(T1 name, T2 age)
	{
		this->m_Name = name;
		this->m_Age = age;
	}

private:
	T1 m_Name;
	T2 m_Age;
};

template<class T1,class T2>
void printPerson2(Person<T1, T2> &p)
{
	cout << "类外实现 --- 姓名： " << p.m_Name << " 年龄： " << p.m_Age << endl;
}

void test01()
{
	Person <string, int> p("Tom", 100);
	printPerson(p);
	printPerson2(p);
	printPerson3(p);
}

int main(){

	test01();

	system("pause");
	return EXIT_SUCCESS;
}