**01：函数模板语法：
#include<iostream>using namespace std;//交换两个整型函数void swapInt(int &a ,int & b){int temp = a;a = b;b = temp;}//交换两个浮点型函数void swapDouble(double& a, double& b){double temp = a;a = b;b = temp;}//函数模板template<typename T> //声明一个模板，T是一个通用的数据类型void mySwap(T& a, T& b){T temp = a;a = b;b = temp;}void test01(){int a = 10;int b = 20;//swapInt(a, b);//利用模板实现交换//1：自动类型推导mySwap(a, b);//2:显示指定类型mySwap<int>(a, b);cout << "a=" << a << endl;cout << "b=" << b << endl;}void test02(){double a = 1.0;double b = 2.0;swapDouble(a,b);cout << "a=" << a << endl;cout << "b=" << b << endl;}int main(){test01();test02();return 0;}
02类模板与函数模板的区别
/*总结：1：类模板使用只能用显示指定类型方式2：类模板中的模板参数列表可以有默认参数*/#include<iostream>using namespace std;#include<string>//类模板template<class NameType, class AgeType=int> //int模板的默认参数class Person{public:NameType m_Name;AgeType m_Age;Person(NameType name, AgeType age){this->m_Name = name;this->m_Age = age;}void showPerson(){cout << "name: " << this->m_Name << "age: " << this->m_Age << endl;}};void test01(){//Person p1("顺悟空",324);错误，无法使用自动类型推导Person<string, int > p1("顺悟空",324); //只能用显示指定类型p1.showPerson();}//类模板在模板参数列表中可以有默认参数void test02(){Person<string>p("猪八戒",9009); //类模板中的模板参数列表 可以指定默认参数p.showPerson();}int main(){test01();test02();return 0;}
03:函数模板案例：
#include<iostream>using namespace std;//实现通用 对数组进行排序的函数//规则 从小到大 //算法 选择//测试： char 数组 int 数组//交换函数的模板template<class T>void mySwap(T& a, T& b){T temp = a;a = b;b = temp;}//选择排序算法template<class T>void mySort(T arr[], int len){for (int i = 0; i < len; i++){int max = i; //认定最大值的下表for (int j = i + 1; j < len; j++){//认定的最大值 比遍历出的数值 要小，说明j下标的元素才是真正的最大值if (arr[max] < arr[j]){max = j; //更新最大值的下标}}if (max != i){//交换max和i元素mySwap(arr[max], arr[i]);}}}//提供打印数组模板template<class T>void printArray(T arr[], int len){for (int i = 0; i < len; i++){cout << arr[i]<<" ";}cout << endl;}void test01(){//测试char数组char charArr[] = "fdgkagja";int len = sizeof(charArr) / sizeof(char);mySort(charArr, len);printArray(charArr, len);}void test02(){int intArr[] = {3,4,5,6,5,8,3,8,29 };int len = sizeof(intArr) / sizeof(int);mySort(intArr, len);printArray(intArr, len);}int main(){test01();test02();return 0;}
04普通函数与函数模板的区别
#include<iostream>using namespace std;//1:普通函数调用可以发生隐式类型转换//2：函数模板 用自动类型推导，不可以发生隐式类型转换//3：函数模板 显式指定类型 ，可以发生隐式类型转换//总结：建议使用显式指定类型的方式 调用函数模板 ，因为可以自己确定通用类型T//普通函数int myAdd01(int a, int b){return a + b;}//函数模板template<class T>T myAdd02(T a ,T b){return a + b;}void test01(){int a = 10;int b = 20;char c = 'c';//a-97 c-99cout << myAdd01(a, c) << endl;//自动类型推导//cout << myAdd02(a, c) << endl;//显式类型转换cout << myAdd02<int>(a, c) << endl;}int main(){test01();return 0;}
05普通函数与函数模板调用规则
#include<iostream>using namespace std;/*1；如果函数模板和普通函数都可以调用，优先调用普通函数2：可以通过空模板参数列表 强制调用 函数模板3：函数模板可以发生函数重载4：如果函数模板可以产生更好的匹配，优先调用函数模板*/void myPrint(int a, int b){cout << "调用普通函数！" << endl;}template<class T>void myPrint(T a, T b){cout << "调用函数模板！" << endl;}template<class T>void myPrint(T a, T b, T c){cout << "调用重载的函数模板！" << endl;}void test01(){int a = 10;int b = 20;//1；如果函数模板和普通函数都可以调用，优先调用普通函数myPrint(a, b);//通过空模板参数列表，强制调用函数模板myPrint<>(a, b);//3：函数模板可以发生函数重载myPrint(a, b, 100); //3个参数char d = 'd';char f = 'd';myPrint(d, f);}int main(){test01();return 0;}
06模板的局限性
/*1：利用具体化的模板，可以解决自定义类型的通用化2：学习模板并不是为了写模板，而是在STL能运用系统提供的模板#include<iostream>using namespace std;#include<iostream>//模板并不是万能的，有些特殊的数据类型，需要用具体化方式做特殊实现*/class Person{public :string m_Name;int m_Age;Person(string name, int age) //初始化{this->m_Name = name;this->m_Age = age;}};template<class T>bool myCompare(T& a, T& b){if (a == b){return true;}else{return false;}}//利用具体化Person的版本实现代码，具体化优先调用template<>bool myCompare(Person& p1, Person& p2){if (p1.m_Name == p2.m_Name && p1.m_Age){return true;}else{return false;}}void test01(){int a = 10;int b = 20;bool ret = myCompare(a, b);if (ret){cout << "a=b" << endl;}else{cout << "a!=b" << endl;}}void test02(){Person p1("Tom", 10);Person p2("Tom", 10);bool ret = myCompare(p1, p2);if (ret){cout << "p1=p2" << endl;}else{cout << "p1!=p2" << endl;}}int main(){test01();test02();return 0;}
07类模板分文件编写.cpp
#include<iostream>using namespace std;#include <string>//#include "Person.h"#include "Person.hpp"/*类模板分文件编写问题以及解决1：直接包含 源文件2：将.h和.cpp 中的内容写到一起，将后缀名改为.hpp*/void test01(){Person<string, int>p("Tom", 324);p.showPerson();}int main(){test01();return 0;}
07-1 Person.hpp
#pragma once#include <iostream>using namespace std;template <class T1, class T2>class Person{public:T1 m_Name;T2 m_Age;Person(T1 name, T2 age);/*{this->m_Name = name;this->m_Age = age;}*/void showPerson();/*{cout << "姓名： " << this->m_Name << "年龄： " << this->m_Age << endl;}*/};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 << "年龄： " << this->m_Age << endl;}
08类模板与友元
#include<iostream>using namespace std;#include<string>//总结：建议全局函数做类内实现，用法简单，而且编译器容易识别//通过全局函数 打印Person信息//2:全局函数配合友元 类外实现 先做函数模板声明，下方再做函数模板定义 ，再做友元template<class T1, class T2>class Person;//如果声明了函数模板，可以将实现写在后面，否则需要将实现体写到类的前面让编译器提前看到//template<class T1, class T2>class Person void printPerson2(Perdon<T1,T2>&p)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;}template<class T1 ,class T2>class Person{//全局函数friend void printPerson(Person<T1, T2>p){cout << "姓名： " << p.m_Name << "年龄： " << p.m_Age << endl;}//全局函数 类外实现//template<class T1, class T2>//friend void printPerson2<>(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;};//；全局函数类外实现//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;//}//全局函数再类内实现void test01(){Person<string, int>p("Tom", 20);printPerson(p);}//全局函数再类外实现void test02(){Person<string, int>p("jon", 40);printPerson2(p);}int main(){test01();test02();return 0;}
MyArray
//创建自己通用的数组#include<iostream>using namespace std;template<class T>class MyArray{public://有参构造函数 参数 容量MyArray(int capacity){this->m_Capacity = capacity;this->m_Size = 0;this->pAddress = new T[this->m_Capacity];}//尾插法void Push_Back(const T & val){//判断容量是否相等if (this->m_Capacity == this->m_Size){return;}this->pAddress[this->m_Size] = val;//再数组末尾插入数据this->m_Size++;//更新数组大小}//尾删法void Pop_Back(){//让用户访问不到最后一个元素，即为尾删，逻辑删除if (this->m_Size == 0){return;}this->m_Size--;}//通过下标方式访问数组//arr[0]=200--要实现左值，要加上&号T& operator[](int index){return this->pAddress[index];}//返回数组的容量int getCapacity(){return this->m_Capacity;}//返回数组大小int getSize(){return this->m_Size;}//拷贝构造函数 防止浅拷贝问题MyArray(const MyArray& arr){this->m_Capacity = arr.m_Capacity;this->m_Size = arr.m_Size;//this->pAddress = arr.pAddress;//深拷贝this->pAddress = new T[arr.m_Capacity];//将arr中的数据都拷贝过来for (int i = 0; i < this->m_Size; i++){this->pAddress[i] = arr.pAddress[i];}}//operator=防止浅拷贝问题MyArray & operator=(const MyArray & myarray){//先判断原来堆区是否有数据，如果有先释放if (this->pAddress != NULL){delete[]this->pAddress;this->m_pAddress = NULL;this->m_Capacity = 0;this->m_Size = 0;}//深拷贝this->m_Capacity = arr.m_Capacity;this->m_Size = arr.m_Size;this->pAddress = new T[arr.m_Capacity];for (int i = 0; i < this->m_Size; i++){this->pAddress[i] = arr.pAddress[i];}return *this;}//析构函数~MyArray(){if (this->pAddress != NULL){delete[]this->pAddress;this->pAddress = NULL;this->m_Capacity = NULL;this->m_Size = 0;}}private:T* pAddress; //指针指向堆区开辟的真实数组int m_Capacity;//数组容量int m_Size;T arr[];};
09类模板案例-数组封装
#include<iostream>using namespace std;#include "MyArray.hpp"#include"string"void printIntArray(MyArray<int>& arr){for (int i = 0; i < arr.getSize(); i++){cout << arr[i] << endl;}cout << endl;}//测试内置 数据类型void test01(){MyArray<int>array1(5);for (int i = 0; i < 5; i++){//用尾插法向数组插入数据array1.Push_Back(i);}cout << "arr1输出结果为： " << endl;printIntArray(array1);cout << "array1的大小：" <<array1.getSize()<< endl;cout << "array的容量：" << array1.getCapacity() << endl;cout << "-----------------------------------------" << endl;MyArray<int>array2(array1);array2.Pop_Back();cout << "array2打印输出： " << endl;printIntArray(array2);cout << "array2的大小：" << array2.getSize() << endl;cout << "array2的容量： " << array2.getCapacity() << endl;}//测试自定义数据类型class Person{public:Person() {};Person(string name, int age){this->m_Name = name;this->m_Age = age;}public:string m_Name;int m_Age;};void printPersonArray(MyArray < Person>& personArr){for (int i = 0;i< personArr.getSize(); i++){cout << "姓名：" << personArr[i].m_Name << "年龄：" << personArr[i].m_Age << endl;}}void test02(){//创建数组MyArray<Person>pArray(10);Person p1("孙悟空", 23);Person p2("悟空", 63);Person p3("孙悟空", 93);Person p4("孙空", 23);Person p5("孙悟", 23);//插入数据pArray.Push_Back(p1);pArray.Push_Back(p2);pArray.Push_Back(p3);pArray.Push_Back(p4);pArray.Push_Back(p5);printPersonArray(pArray);cout << "pArray 的大小：" << pArray.getSize() << endl;cout << "pArray的容量：" << pArray.getCapacity() << endl;}int main(){test01();test02();return 0;}
模板 （函数模板语法 类模板与函数模板的区别 :函数模板案例 普通函数与函数模板的区别 普通函数与函数模板调用规则 模板的局限性 类模板分文件编写.cpp Person.hpp 类模板与友元）
