计算器

#include <iostream>using std::ostream;using namespace std;template<typename T>class calculator{public:calculator(){}calculator(const T a);    calculator&operator+(calculator&p);calculator&operator-(calculator&p);calculator&operator/(calculator&p);calculator&operator*(calculator&p);void display()const;~calculator(){}private:T a;};template<typename T>calculator<T>::calculator(const T a):a(a){   cout<<"the calculator is initializing";cout<<endl;}template<typename T>calculator<T>&calculator<T>::operator+(calculator<T>&p){ this->a+=p.a;return *this;}template<typename T>calculator<T>&calculator<T>::operator-(calculator<T>&p){this->a-=p.a;return *this;}template<typename T>calculator<T>&calculator<T>::operator*(calculator<T>&p){this->a*=p.a;return *this;}template<typename T>calculator<T>&calculator<T>::operator/(calculator<T>&p){this->a/=p.a;return *this;}template<typename T>void calculator<T>::display()const{cout<<a;}int main(){calculator<int> P(1);calculator<int> P2(2);calculator<int> p3;calculator<int> p4;calculator<int> p5;calculator<int> p6;p6=P2-P;p6.display();system("pause");return 0;}