simple C++ iterator

一个简单的迭代器的实现。

#include <iostream>
#include <cassert>
using namespace std;


template <typename T>
class MyVector
{
public:
    class MyIterator
    {// override * ++ -- = [] + == !=

    public:
        MyIterator():iterHandle(0),iterIndex(0){};
        //MyIterator(T* ptr){
        //    iterHandle = ptr;
        //    iterIndex = 0;
        //};
        ~MyIterator(){};

        T &operator * ()
        {
            return *iterHandle;
        }

        MyIterator& operator++()
        {
            iterHandle = iterHandle+1;
            iterIndex = iterIndex+1;
            return *this;
        }

        MyIterator& operator--()
        {
            iterHandle = iterHandle-1;
            iterIndex = iterIndex-1;
            return *this;
        }

        MyIterator& operator=(T * otherIt)
        {
            iterHandle = otherIt;
            return *this;
        }

        MyIterator& operator +(int n)
        {
            iterHandle += n;
            iterIndex += n;
            return *this;
        }
        int index()
        {
            return iterIndex;
        }
        bool operator==(T * otherIt)
        {
            return iterHandle==otherIt;
        }
        bool operator!=(T * otherIt)
        {
            return iterHandle!=otherIt;
        }

    private:
        T * iterHandle;
        int iterIndex;
    };

    MyVector(){
        mySize = 1;
        myData = malloc(sizeof(T));
    };
    MyVector(int sizeT){
        mySize = sizeT;
        int temp = sizeof(T)*sizeT;
        myData = (T*)malloc(temp);
        for(int i=0;i<sizeT;i++)
        {
            myData[i] = 0;
        }

    };
    //MyVector(int sizeT);
    ~MyVector(){
        free(myData);
        myData = NULL;
        mySize = 0;
    };

    T &operator [](int n)
    {
        return myData[n];
    }
    T *begin()
    {
        return (myData);
    }
    T *end()
    {
        return (myData+mySize);
    }
    int size()
    {
        return mySize;
    }

    void clear()
    {
        free(myData);
        myData = NULL;
        mySize = 0;
    }
    void push_back(const T tempVlue)
    {
        T * handleTemp;
        mySize +=1;
        handleTemp = (T*)malloc(sizeof(T)*(mySize));
        for(int i=0;i<mySize-1;i++)
        {
            handleTemp[i] = myData[i];
        }
        handleTemp[mySize-1] = tempVlue;
        free(myData);
        myData = handleTemp;
        handleTemp = NULL;
    }

private:
    T* myData;
    int mySize;

};

#include "MyVector.h"
#include <vector>
#include <iterator>
#include <iostream>
#include <algorithm>
using namespace std;


void printT(float x)
{
    cout << x << endl;
}
int main()
{
    vector<int> vec(3);
    fill(vec.begin(),vec.end(),3);
    vector<int>::iterator iter = vec.begin();

    for(;iter != vec.end();iter++)
    {
        cout<<*iter<<endl;
    }

    cout<<"
"<<endl;

    MyVector<float> vec2(3);
    MyVector<float>::MyIterator iter2;
    vec2[0] = 2;
    vec2[1] = 3;
    vec2[2] = 4;

    iter2=vec2.begin();
    for(;iter2!=vec2.end();++iter2)
    {
        cout<<*(iter2)<<endl;
    }
    for_each(vec2.begin(), vec2.end(),printT);
    //auto f = [](float x) {cout << x <<endl;};
    //for_each(vec2.begin(), vec2.end(), f);
    //int a = 1;
    //int b = 2;
//
    //auto f = [a,b](int c){return a+b+c;};
    //test(f);
    return 0;
}

输出结果。

3
3
3


2
3
4
2
3
4

Process finished with exit code 0

有两个问题：

第一个，不支持lambda表达式，c++完全支持，gcc版本是4.9.2,clion自带cmake版本是3.7.2.

第二个是类型转换的疑惑，begin和end都赋值给了迭代器，有疑惑的是什么时候进行了类型转换。经过大神提示，我自己写的重载operate=自己都没注意到-。-。囧！