c++类模板，嵌套类模板，模板链表，动态数组

c++类模板，嵌套类模板，模板链表，动态数组

一.类模板

1.类模板的书写

代码如下

template<typename T>//模板
class CTest {//类
public:T m_a;CTest(const T&a):m_a(a){}void fun1() {cout << typeid(m_a).name() << "   " << m_a << endl;}
};int main() {//进行调用测试CTest<int> tes(5);//在定义对象时 显示指定tes.fun1();CTest2<> tes2(5);//用类模板定义对象时<> 不能省略tes2.fun1();return 0;
}

2.类模板的顺序要求

指定默认的类型有顺序要求，从右到左一次指定，中间不得有间断

代码如下

template<typename T=int, typename K=char>//正确的写法

3.当类模板中有函数模板时，在外面进行函数实现

在类模板里定义了使用了函数模板的函数

在类模板外进行实现没使用函数模板的函数的时候

只写类模板就可以

代码如下

template<typename T=int>
class CTest {
public:T m_a;CTest(const T& a) :m_a(a) {}void fun1();template<typename K=char>void fun2(K k);
};template<typename T>
void CTest<T>::fun1() {cout << typeid(m_a).name() << "   " << m_a << endl;
}

在类模板外进行实现使用了函数模板的函数的时候

要先类模板，后函数模板，顺序不能反

代码如下

template<typename T=int>
class CTest {
public:T m_a;CTest(const T& a) :m_a(a) {}void fun1();template<typename K=char>void fun2(K k);
};template<typename T>//类模板
template<typename K>//函数模板
void CTest<T>::fun2(K k) {cout << typeid(m_a).name() << "   " << m_a << endl;cout << typeid(k).name() << "   " << k << endl;
}

二.嵌套类模板

看如下代码进行分析

#include <iostream>
using namespace std;template<typename T>
class A {
public:T m_a;A(const T&a):m_a(a){}};class B {
public:A<int> aa;B():aa(1) {//调用了A的构造函数}
};template<typename K>
class C {
public:A<K> aa;C(const A<K>& a):aa(a){}//调用了A的拷贝函数
};template<typename M>
class D {
public:M m_m;D(const M& m) :m_m(m) {}//调用了A的拷贝函数
};int main() {B tes;cout << typeid(tes.aa.m_a).name() << "   "<< tes.aa.m_a <<endl;C<char> cc(A<char>('a'));cout << typeid(cc.aa.m_a).name() << "   " << cc.aa.m_a << endl;D<  A<char> > dd(A<char>('a'));cout << typeid(dd.m_m.m_a).name() << "   " << dd.m_m.m_a << endl;return 0;
}

三.模板链表

将一个链表变为模板链表

原链表

#include <iostream>
using namespace std;//节点
struct Node {int m_v;Node* m_pNext;Node(int v) {m_v = v;m_pNext = nullptr;}
};//迭代器
class Citerator {
public:Node* Temp;Citerator(Node* m_pHead) :Temp(m_pHead) {}bool operator!=(Node* m_pHead) {return Temp != m_pHead;}operator bool() {return Temp;}int operator*() {return Temp->m_v;}Node* operator++() {Temp=Temp->m_pNext;return Temp;}Node* operator++(int) {Node* temp = Temp;Temp = Temp->m_pNext;return temp;}};//链表
class Clist {
public:Node* m_pHead;Node* m_pEnd;int m_nLen;
public:void showClist() {Citerator ite(m_pHead);//构造while (ite!=nullptr) { //operator!=  operator==  operator boolcout << *ite << "    ";//operator*ite++;//operator++}cout << endl;}Clist() {m_pHead = m_pEnd = nullptr;m_nLen = 0;}~Clist() {Node* pTemp = nullptr;while (m_pHead) {pTemp = m_pHead;m_pHead = m_pHead->m_pNext;delete pTemp;pTemp = m_pHead = m_pEnd = nullptr;m_nLen = 0;}}void pushBack(int v) {Node* p_Node = new Node(v);if (m_pHead) {m_pEnd->m_pNext = p_Node;m_pEnd = p_Node;}else {m_pHead = m_pEnd = p_Node;}++m_nLen;}void clearFront() {if (m_pHead) {Node* Temp = m_pHead;if (m_nLen == 1) {m_pHead = m_pEnd = nullptr;}else {m_pHead = m_pHead->m_pNext;}delete Temp;Temp = nullptr;--m_nLen;}}int Clistlen() {return m_nLen;}
};int main() {Clist pro;pro.pushBack(1);pro.pushBack(2);pro.pushBack(3);pro.pushBack(4);pro.pushBack(5);pro.showClist();cout << pro.m_nLen << endl;pro.clearFront();pro.clearFront();pro.clearFront();pro.clearFront();pro.showClist();cout << pro.m_nLen << endl;return 0;
}

更改后的链表

#include <iostream>
using namespace std;//节点
template<typename T>//1
struct Node {T m_v; //2Node* m_pNext;Node(const T& v):m_v (v), m_pNext(nullptr){//3}
};//迭代器
template<typename M>//4
class Citerator {
public:Node<M>* Temp;//5Citerator(Node<M>* m_pHead) :Temp(m_pHead) {}//6bool operator!=(Node<M>* m_pHead) {//7return Temp != m_pHead;}operator bool() {return Temp;}M& operator*() {//8 返回类型为引用，返回的就是当前类对象的变量return Temp->m_v;}Node<M>* operator++() {//9Temp=Temp->m_pNext;return Temp;}Node<M>* operator++(int) {//10Node<M>* temp = Temp;//11Temp = Temp->m_pNext;return temp;}};//链表
template<typename K>//12
class Clist {
public:Node<K>* m_pHead;//13Node<K>* m_pEnd;//14int m_nLen;
public:void showClist() {Citerator<K> ite(m_pHead);//构造while (ite!=nullptr) { //operator!=  operator==  operator boolcout << *ite << "    ";//operator*ite++;//operator++}cout << endl;}Clist() {m_pHead = m_pEnd = nullptr;m_nLen = 0;}~Clist() {Node<K>* pTemp = nullptr;//15while (m_pHead) {pTemp = m_pHead;m_pHead = m_pHead->m_pNext;delete pTemp;pTemp = m_pHead = m_pEnd = nullptr;m_nLen = 0;}}void pushBack(K v) {//16Node<K>* p_Node = new Node<K>(v);//17if (m_pHead) {m_pEnd->m_pNext = p_Node;m_pEnd = p_Node;}else {m_pHead = m_pEnd = p_Node;}++m_nLen;}void clearFront() {if (m_pHead) {Node<K>* Temp = m_pHead;//18if (m_nLen == 1) {m_pHead = m_pEnd = nullptr;}else {m_pHead = m_pHead->m_pNext;}delete Temp;Temp = nullptr;--m_nLen;}}int Clistlen() {return m_nLen;}
};//自定义类型
class CTest {
public:int m_a;CTest():m_a(10){}CTest(int a):m_a(a) {}
};ostream& operator<<(ostream& os, CTest& tst) {os << tst.m_a;return os;
}
int main() {//样例测试//Clist<double> pro;//pro.pushBack(1.1);//pro.pushBack(2.1);//pro.pushBack(3.1);//pro.pushBack(4.1);//pro.pushBack(5.1);//pro.showClist();//cout << pro.m_nLen << endl;//pro.clearFront();//pro.clearFront();//pro.clearFront();//pro.clearFront();//pro.showClist();//cout << pro.m_nLen << endl;//自定义类型的测试Clist<CTest> pro;pro.pushBack(CTest());pro.pushBack(CTest());pro.pushBack(CTest());pro.pushBack(CTest(5));pro.pushBack(CTest(57));pro.showClist();cout << pro.m_nLen << endl;pro.clearFront();pro.clearFront();pro.clearFront();pro.clearFront();pro.showClist();cout << pro.m_nLen << endl;return 0;
}

四.动态数组

动态数组：

1.用模板使该数组变为通用类型（可以存任意一种类型的数据）

2.当数组大小不够时，以1.5倍扩容

代码如下

#include <iostream>
using namespace std;/*动态数组：可以存任意一种类型数据所以要用到模板当数组大小不够时，以1.5倍扩容
*/template<typename T>
class CDynamicArray {
public:T * array;int m_size;  //使用量int m_rongliang;  //容量
public:CDynamicArray(int rongliang=0):array(nullptr), m_size(0), m_rongliang(0){//动态数组的初始化if (rongliang > 0) {array = new T[rongliang];m_size = 0;m_rongliang = rongliang;}}~CDynamicArray() {//最后结束回收空间if (array) {delete[]array;}m_size = 0;m_rongliang = 0;}
public:void PushBack(const T& t) {if (m_size >= m_rongliang) {//容量不够，进行扩容int Temp = m_rongliang + 1;m_rongliang = (m_rongliang + m_rongliang / 2)> Temp? (m_rongliang + m_rongliang / 2): Temp;T* Newarray = new T[m_rongliang];for (int i = 0; i < m_size; i++) {Newarray[i] = array[i];}delete[]array; array = Newarray;}array[m_size++] = t;}void PopBack() {//删除动态数组尾部元素if (m_size) m_size -= 1;}void ShowArray() {//遍历一遍动态数组元素for (int i = 0; i < m_size; i++) {cout << array[i] << "   ";}cout << endl;}int GetLength() {//获取动态数组的长度（使用量）return m_size;}T& operator[](int index) {//重载[]，可以直接通过类对象名[]的方式获得元素的值return array[index];}T* begin() {//手写begin()函数，和end()函数，这样就可以使用for的范围遍历了return &array[0];}T* end() {return &array[m_size];}};int main() {//样例测试CDynamicArray<int> arr;arr.PushBack(1);arr.PushBack(2);arr.PushBack(3);arr.PushBack(4);arr.PushBack(5);arr.ShowArray();cout << arr.GetLength() << endl;arr.PopBack();arr.PopBack();arr.ShowArray();cout << arr[0] << endl;for (int i = 0; i < arr.GetLength(); i++) {cout << arr[i] << "   ";}cout << endl;for (int v : arr) {cout << v << "   " ;}cout << endl;return 0;
}