類模板碰到繼承問題

基類如果是模板類，必須讓子類告訴編譯器 基類中的T到底是什么類型

如果不告訴，那么無法分配內存，編譯不過

利用參數列表class Child :public Base<int>

#include<iostream>using namespace std;template<class T>class Base{public:T m_A;};//Child繼承于Base必須告訴base中的T的類型，否則T無法分配內存class Child :public Base<int>{};//Child2也是模板類template<class T1,class T2>class Child2 :public Base<int>{public:Child2(){cout << typeid(T1).name ()<< endl;cout << typeid(T2).name ()<< endl;}public:T1 m_B;};void test01(){Child2<int, double >child;//由用戶來指定類型}int main(){test01();system("pause");return 0;}

類模板類外實現

template<class T1 ,class T2>
Person<T1, T2>::Person(T1 name, T2 age)

#include<iostream>#include<string>using namespace std;template<class T1,class T2>class Person{public:Person(T1 name, T2 age);/*{this->m_Name = name;this->m_Age - age;}*/void showPerson();/*{cout << "姓名" << this->m_Name << "年齡" << this->m_Age << endl;}*/T1 m_Name;T2 m_Age;};//類外實現成員函數template<class T1 ,class T2>Person<T1, T2>::Person(T1 name, T2 age){this->m_Name = name;this->m_Age = age;}template<class T1, class T2>void Person<T1, T2>::showPerson(){cout << "姓名" << this->m_Name << "年齡" << this->m_Age << endl;}void test01(){Person <string,int >p1("Mt", 100);p1.showPerson();}int main(){test01();system("pause");return 0;}

類模板與友元函數

友員函數類內實現

#include<iostream> #include<string> using namespace std;template<class T1,class T2>class Person {//友員函數類內實現friend void printPerson(Person<T1,T2>&p){cout << "姓名：" << p.m_Name << "年齡：" << p.m_Age << endl;} public:Person(T1 name, T2 age){this->m_Name = name;this->m_Age = age;}private:T1 m_Name;T2 m_Age; };void test01(){Person<string, int >p("Tom", 10);printPerson(p); }int main() {test01();system("pause");return 0; }

友員函數類內實現

#include<iostream> #include<string> using namespace std;//讓編譯器提前看到printPerson聲明 template<class T1, class T2>class Person; template<class T1, class T2>void printPerson(Person<T1, T2>&p);template<class T1, class T2>class Person {//友員函數類內實現 利用空參數列表 告訴編譯器 模板函數聲明friend void printPerson<>(Person<T1, T2>&p); //普通函數 聲明/*{cout << "姓名：" << p.m_Name << "年齡：" << p.m_Age << endl;}*/ public:Person(T1 name, T2 age){this->m_Name = name;this->m_Age = age;}private:T1 m_Name;T2 m_Age; };//類外實現 template<class T1,class T2>void printPerson(Person<T1, T2>&p) {cout << "姓名：" << p.m_Name << "年齡：" << p.m_Age << endl; }void test01(){Person<string, int >p("Tom", 10);printPerson(p); }int main() {test01();system("pause");return 0; }

總結

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