类、函数模板、类模板、函数重载的集体应用

测试代码如下：

#include <bits/stdc++.h>
using namespace std;

class Base{
public:
	int num;
public:
	friend void operator+(const Base &ob1,const Base &ob2);
	Base(){}
	Base(int num){
		this->num=num;
	}
	~Base(){}
};

void operator+(const Base &ob1,const Base &ob2){
		cout<<ob1.num+ob2.num<<endl;
	}

template<class T>//类模板用class 
class Test: public Base
{
	template<typename T1>
	friend ostream& operator<< (ostream &out, Test<T1> ob);
private:
	T* arr;
	int capacity;
	int size;
public:
	Test(){
		capacity=5;
		size=0;
		arr=new T [5];
		memset(arr,0,capacity*sizeof(T));
	}
	Test(int capacity){
		this->capacity=capacity;
		this->size=0;
		arr=new T [capacity];
		memset(arr,0,sizeof(T)*capacity); 
	} 
	Test(const Test &ob){
		capacity=ob.capacity;
		size=ob.size;
		arr=new T [capacity];
		memcpy(arr,ob.arr,sizeof(T)*capacity);
	}
	~Test(){
		if(arr!=NULL){
			delete [] arr;
			arr=NULL;
		}
		capacity=0;
			size=0;
	}
};
//函数作为类模板的友元,用typename 
template<typename T1>
ostream& operator<< (ostream &out,Test<T1> ob){
	out<<"capacity:"<<ob.capacity<<" size:"<<ob.size<<endl;
	return out;
}

int main(){
	Base ob1(1);
	Base ob2(2);
	Test<int> ob3(10);
	cout<<ob2.num<<ob1.num<<endl;
	cout<<ob3<<endl;
	return 0;
}