使用类模板的C++线性表实现（数组方式）

main.h

#ifndef _MAIN_H_
#define _MAIN_H_

#include 
#include 
#include 

using namespace std;

//用于改变一维数组的长度
template<class T>
void changeLength1D(T* a,int oldlength,int newlength)
{
    if (newlength > 0)
    {
        T* extraBlocks = new T[newlength];    //用新长度先分配一块额外空间
        int copylen = min(oldlength, newlength);    //确认要拷贝的长度
        copy(a, a + copylen, extraBlocks);    //老数组的数据拷贝到新分配的空间
        delete []a;    //删除老数组的指针
        a = extraBlocks;    //指针指向新区域
    }
    else
    {
        throw 2;
    }

}

//抽象基类
template<class T>
class LinearList
{
public:
    virtual ~LinearList() {};
    virtual bool empty() const = 0;
    virtual T& get(int index) const = 0;
    virtual int indexof(const T& element) const = 0;
    virtual void erase(int index) const = 0;
    virtual void insert(const int index, const T& element) = 0;
    virtual void output() const = 0;

};

//数组类定义
template<class T>
class arraylist : LinearList
{
public:
    arraylist(int initialCapacity = 10);
    arraylist(const arraylist&);
    ~arraylist() { delete[]element; }
    bool empty() const { return listSize == 0; }
    int size() const{ return listSize; }
    T& get(int index) const;
    int indexof(const T& element) const;
    void erase(int index) const;
    void insert(const int index, const T& element);
    void output() const;
    
    //新定义的方法
    int capacity()const { return arrayLength; }

protected:
    void checkIndex(int index)const;
    T* element;
    int arrayLength;
    int listSize;
};

//数组类实现
template<class T>
arraylist::arraylist(int initialCapacity)    //默认构造函数，初始容量默认值为10
{
    if (initialCapacity < 1)
    {
        throw 0;    //抛出的异常用整形数字处理
    }
    else
    {
        //do nothing
    }

    arrayLength = initialCapacity;
    element = new T[arrayLength];    //分配数组空间
    listSize = 0;
}

template<class T>
arraylist::arraylist(const arraylist& theList)    //复制构造函数
{
    arrayLength = theList.arrayLength;
    listSize = theList.listSize;
    element = new T[arrayLength];    
    copy(theList.element, theList.element + listSize, element);
}

template<class T>
void arraylist::checkIndex(int index)const    //检查下标
{
    if (index < 0 || index >= listSize)
    {
        throw 1;
    }
    else
    {
        //do nothing
    }
}

template<class T>
T& arraylist::get(int index) const    //获取某下标的元素
{
    checkIndex(index);
    return element[index];
}

template<class T>
int arraylist::indexof(const T& theElement) const    //获取某元素的下标
{
    int foundindex = (int)(find(element, element + listSize, theElement) - element);

    if (foundindex == listSize)
        return -1;
    else return foundindex;
}

template<class T>
void arraylist::erase(int index) const
{
    checkIndex(index);

    //从index+1开始，所有元素左移一格
    copy(element + index + 1, element + listSize, element + index);

    int sizeTemp = listSize;
    sizeTemp--;
    element[--sizeTemp].~T();    //调用析构函数删除元素

}

template<class T>
void arraylist::insert(const int index, const T& theElement)    //特定位置插入元素
{
    if (index < 0 || index > listSize)
    {
        throw 1;
    }
    else
    {
        //do nothing
    }

    //数组长度达到容量，容量加倍
    if (listSize == arrayLength)
    {
        changeLength1D(element, arrayLength, 2 * arrayLength);
        arrayLength *= 2;
    }
    else
    {
        //do nothing
    }

    copy_backward(element + index, element + listSize, element + listSize + 1);
    element[index] = theElement;
    listSize++;
}

template<class T>
void arraylist::output() const
{
    for (int i = 0; i < listSize; i++)
    {
        cout << element[i] << " ";
    }
    cout << endl;
}


#endif

 

main.cpp

#include "main.h"

int main()
{
    arraylist<int> a1;

    try
    {
        a1.insert(0, 1);
        a1.insert(1, 2);
        a1.insert(2, 3);

        a1.output();

        a1.insert(0, 4);

        a1.output();
    }
    catch (const int errornum)
    {
        if (errornum == 0)
        {
            cout << "Initial capacity must be >0!\n";
        }
        else if (errornum == 1)
        {
            cout << "Array index illegal!\n";
        }
        else if(errornum == 2)
        {
            cout << "New array length must be >0!\n";
        }
    }

    return 0;
}