使用类模板实现STL Vector,点击查看代码

#include <iostream>
using namespace std;

template<typename T>
class MyVector {

public:

//构造函数
MyVector<T>(int size = 10) {
    T * _tep = new T[size]();
    first = _tep;
    last = _tep;
    end = first + size;//
    cout << "构建Vector，首地址" << first << endl;
}

//拷贝构造
MyVector<T>(const MyVector<T> & _src) {

    //对方vector是为空
    if (_src.Empty()) {
        int srcVectorySize = _src.getVectorSize();
        T * _tep = new T[srcVectorySize]();
        first = _tep;
        last = _tep;
        end = first + srcVectorySize;//
        cout << "拷贝构造构建Vector,空拷贝" << endl;
    }
    else {

        int srcVectorySize = _src.getVectorSize();
        T * _tep = new T[srcVectorySize]();
        first    = _tep;
        last     = _tep;
        end      = first + srcVectorySize;//
        T *      _srcVectorElementPoint = _src.first;
        while (_srcVectorElementPoint < _src.last) {
            *_tep = *_srcVectorElementPoint;
            _tep++;

            _srcVectorElementPoint++;
        }//end
        last=_tep;
        cout << "拷贝构造构建Vector" << endl;
    }

}

//赋值函数
MyVector<T> & operator=(const MyVector<T> & _src)
{
    //避免重复
    if (this == &_src) { return *this; }

    //释放现有堆上资源空间
    if (this->Empty() == false) {
        delete[]first;
        first = nullptr;
        last = nullptr;
        end = nullptr;
    }

    int srcVectorySize = _src.getVectorSize();
    T * _tep = new T[srcVectorySize]();
    first = _tep;
    last = _tep;
    end = first + srcVectorySize;//
    T *      _srcVectorElementPoint = _src.first;
    while (_srcVectorElementPoint < _src.last) {
        *_tep = *_srcVectorElementPoint;
        _tep++;
        _srcVectorElementPoint++;
    }//end
    last = _tep;
    cout << "赋值函数构建Vector" << endl;
}

//析构函数
~MyVector<T>() {
    if (Empty() == false) {
        delete[]first;
        first = nullptr;
        last  = nullptr;
        end   = nullptr;
        cout << "析构Vector,堆地址"<<first << endl;
    }

}

//添加值,返回指向当前元素的指针,返回为 const * 不允许修改
const T * addValue(const T & _srcValue) {

    //满空间,两倍扩容
    if (Full()) {
        Expend();
    }
    *last = _srcValue;
    last++;
    cout << "Vector添加元素,元素地址" << last << endl;

    return last;

}

//获取指定下标的值
T getValue(int index) const {
    if (index<0) { return *first; }
    if (index > this->getVectorSize()) { return *(last-1); }
    int flag = 0;
    T  *elementPoint = first;
    while (flag < index) {
        elementPoint++;
        flag++;
    }
    cout << "获取Vector元素值,元素地址" << elementPoint <<"元素值"<< *elementPoint << endl;
    return *elementPoint;
}

//编辑指定下标元素的值,返回当前节点的指针 不允许通过返回指针修改
const T * eidtValue(int index,const T & _value) {

    if (index > this->getVectorSize() || index<0) { return nullptr; }
    int flag = 0;
    T  *elementPoint = first;
    while (flag < index) {
        elementPoint++;
        flag++;
    }
    *elementPoint = _value;
    cout << "编辑Vector元素值,元素地址" << elementPoint << "元素值" << *elementPoint << endl;
    return elementPoint;
}

//判断是否为空
bool Empty() const {
    if (first == last) { return true; }
    return false;
}
//判断空间是否满
bool Full() const{
    if (last == end) { return true; }
    return false;
}

int getVectorSize() const {
    return this->end - this->first;
}

void printVector() const {

    cout << "打印数组元素" << endl;
    T  *elementPoint = first;
    int index = 0;

    while (elementPoint < last)
    {
        cout.precision(4);
        cout << "[" << index << "]=" << (*elementPoint) <<"该元素地址="<< elementPoint << endl;
        elementPoint++;
        index++;
    }
}

private:
    T * first;
    T * last;
    T * end;

    //两倍扩容
    void Expend() {

        int size = this->getVectorSize();

        int newSize  = size * 2;
        T  *newFirst = new T[newSize];
        T  *newLast  = newFirst;
        T  *newEnd   = newFirst + newSize;
        const T  *srcElementPoint = this->first;
        while (srcElementPoint < this->last) {
            *newLast = *srcElementPoint;
            newLast++;
            srcElementPoint++;
        }

        //释放原有空间
        delete[]first;
        first = nullptr;
        last = nullptr;
        end = nullptr;

        first = newFirst;
        last = newLast;
        end = newEnd;

        cout << "两倍扩容新堆内存地址"<< first << endl;
    }

};

int main() {

    MyVector<int> v1 (6) ;

    v1.addValue(10);
    v1.addValue(9);
    v1.addValue(8);
    v1.addValue(7);
    v1.addValue(6);
    v1.addValue(5);

    v1.printVector();
    v1.addValue(4.0);
    v1.printVector();

    v1.eidtValue(2, 100);
    v1.printVector();

    int getValue = v1.getValue(3);

    cout << "getValue =" << getValue << endl;

    MyVector<int> v2 = v1;

    v2.printVector();

    MyVector<int> v3(10);
    v3 = v1;
    v3.printVector();
    system("pause");

    return 1;
}