实现vector基本功能

第一次写博客，很是兴奋！

由于最近网上看到很多面试管对STL算法较感兴趣，于是就想自己写个vector容器，实现STL内部自带的基本功能。借鉴于博主yysdsyl写的vector，很是感谢！

下面是整个vector包装。

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为了实现vetor的排序功能，我选择了快排

#ifndef COMMON_ZHAOYAN_HHH#define COMMON_ZHAOYAN_HHH#include "resource.h"////////////////////////////////////////////////////////////////////////////////////*                       1  sort   2  reverse                                    *////////////////////////////////////////////////////////////////////////////////////template <typename T> extern void QuickSort(T a[] , size_t m , size_t n , size_t mode){        if(m < n){        T temp = a[m];        size_t i = m , j = n;        while(m < n){            if(mode == 2)   while(temp >= a[n] && m < n) -- n;            else while(temp <= a[n] && m < n) -- n;            if(m < n) swap(a[n] , a[m]);            if(mode == 2) while(temp <= a[m] && m < n) ++ m;            else while(temp >= a[m] && m < n) ++ m;            if(m < n) swap(a[m] , a[n]);        }        QuickSort(a , m + 1 , j , mode);        if(m == 0) m = 1;        QuickSort(a , i , m - 1 , mode);            }else return;    }#endif 

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为了防止出现异常，我添加了很小的异常判断

#ifndef RESOURCE_ZY_HHH#define RESOURCE_ZY_HHH#include "iostream"#include<cstddef>#include<cassert>#include "string"#include "exception" using namespace std;class MyException : public exception{public:    MyException(const string whatString):exception（whatString）

    {        cout << whatString << endl;    }};#endif

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下面是vector的基本功能，包括元素数目，排序，插入，删除，添加，倒序等功能

#ifndef MYVECTOR_ZY_HHHH#define MYVECTOR_ZY_HHHH#include "resource.h"#include "common.h"///////////////////////////////////////////////////////////////////*            实现vector容器基本功能                      *///////////////////////////////////////////////////////////////////template <typename T> class MyVector{public:MyVector(size_t size , size_t init = 0);MyVector();        ~MyVector();void push_back(T);size_t GetSize();void ReSize(size_t size , size_t init = -1);T& operator[](size_t i);        T* begin();        void clear();        void erease(size_t i);        void insert(size_t num , size_t i);        void sort();        void reverse();        void SWAP(size_t a , size_t b);private:T*      data;size_t  RSize;//数组中元素具体数目

size_t  PSize;//数组开辟的大小

} ;template <typename T> MyVector<T>::MyVector():PSize(1024){    this->data = (T* )malloc(sizeof(T) * PSize);    this->RSize = 0;}template <typename T> void MyVector<T>::SWAP(size_t a , size_t b){    assert(this->RSize >= 2);    T temp = this->data[a];    this->data[a] = this->data[b];    this->data[b] = temp;}template <typename T> void MyVector<T>::erease(size_t i){    if(i < 0 || i > this->RSize)throw MyException("out of vector border!");    else{        T* p = (T* )malloc(sizeof(T) * this->PSize);        copy(this->data , this->data + i , p);        copy(this->data + i + 1 , this->data + this->RSize , p + i);        free(this->data);        -- this->RSize;        this->data = p;    }}template <typename T> void MyVector<T>::insert(size_t num , size_t i){    if(i < 0 || i > this->RSize) throw MyException("out of vector border!");    else{        if(this->RSize == this->PSize)  this->PSize *= 2;        T* p = (T* )malloc(sizeof(T) * this->PSize);        copy(this->data , this->data + i , p);        p[i] = num;        copy(this->data + i , this->data + this->RSize , p + i + 1);        free(this->data);        ++ this->RSize;        this->data = p;    }}template <typename T> void MyVector<T>::clear(){    this->RSize = 0;    free(this->data);}template <typename T> MyVector<T>::MyVector(size_t size , size_t init = 0):PSize(1024){    assert(size >= 0);    if(size == 0){        this->data = NULL;        this->RSize = 0;    }else{        while(this->PSize <= size)            this->PSize *= 2;        this->data = (T* )malloc(sizeof(T) * this->PSize);        memset(data , init , sizeof(T) * size);        new(this->data) T[size];        this->RSize = size;    }}template <typename T> MyVector<T>::~MyVector(){ /*   free(this->data);    this->data=NULL;    this->RSize = 0;    this->PSize = 0;*/}template <typename T> void MyVector<T>::push_back(T num){    if(this->RSize == this->PSize){        this->PSize *= 2;        T* p = (T* )malloc(sizeof(T) * (this->PSize));        memcpy(p , this->data , sizeof(T) * RSize);        free(this->data);        this->data = p;    }    memcpy(&(this->data[this->RSize]),&num,sizeof(num));    ++ this->RSize;}template <typename T> void MyVector<T>::ReSize(size_t size , size_t init = -1){    if(init != -1) memset(this->data , init , sizeof(T) * size);    if(this->RSize > size)  this->RSize = size;    new(this->data)T[size];}template <typename T> size_t MyVector<T>::GetSize(){    return this->RSize;}template <typename T> T* MyVector<T>::begin(){    return this->data;}template <typename T> T& MyVector<T>::operator[](size_t i){    if(i < 0 || i >this->RSize - 1){        throw MyException("out of vector border!");        exit(0);    }else return this->data[i];    }template <typename T> void MyVector<T>::sort(){    if(this->RSize == 0) throw MyException("no element in MyVector!");    else{        QuickSort(this->data , 0 , this->RSize - 1 , 1);    }}template <typename T> void MyVector<T>::reverse(){    if(this->RSize == 0) throw MyException("no element in MyVector!");    else{        QuickSort(this->data , 0 , this->RSize - 1 , 2);    }}#endif

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下面是测试函数

#include "MyVector.h"int main(){    MyVector<int> vec;    MyVector<MyVector<int>> v;    for(int i = 0; i < 12; ++ i)     {         vec.push_back(i);         cout<<vec[i]<<endl;    }    v.push_back(vec);    v[0].push_back(2);    int i = 0;    try{        //vec.sort();        for(i = 0; i < v.GetSize(); ++ i){            for(int j = 0; j < v[i].GetSize(); ++ j)              printf("%d " ,v[i][j]);        }    }catch(MyException e){        cout << i << endl;    }        return 0;}

结果如下：

整个过程中难点在于指针地址的复制与赋值，浅复制和深复制，还有析构函数的工作原理。不过对于析构函数还是有点疑惑，当对象传进去时，在局部变量自动释放的时候如何不调用析构函数呢？希望大神能给予指点迷津。