template myvector

#include <cstdlib>

#ifndef MYVECTOR_H_INCLUDED
#define MYVECTOR_H_INCLUDED

template <class T>
class MyVector
{
    int vsize;
    int maxsize;
    T *array;
    void alloc_new();
    void dealloc();
public:
    MyVector();
    MyVector(int );
    ~MyVector();
    void push_back(T);
    void pop_back();
    int size();
    T operator[](int);
    T& at(int i);
};

template<class T>
MyVector<T> :: MyVector()
{
    maxsize=5;
    array=new T[maxsize];
    vsize=0;
}

template<class T>
MyVector<T> :: MyVector(int i)
{
    maxsize=i;
    array=new T[maxsize];
    vsize=0;
}

template<class T>
MyVector<T> :: ~MyVector()
{
    delete[] array;
}

template<class T>
void MyVector<T> :: push_back(T i)
{
    if(vsize+1>maxsize)
        alloc_new();
    array[vsize]=i;
    vsize++;
}

template<class T>
T MyVector<T> :: operator[](int i)
{
    return array[i];
}

template<class T>
T& MyVector<T> :: at(int i)
{
    if(i<vsize)
        return array[i];
    std::cout<<"Error: Out of range";exit(1);
}

template<class T>
void MyVector<T> :: pop_back()
{
    if(vsize>0)
    {
        vsize--;
        dealloc();
    }
}

template<class T>
void MyVector<T> :: dealloc()
{
    T* temp;
    temp=new T[vsize];
    for(int i=0;i<vsize;i++)
        temp[i]=array[i];
    delete []array;
    array=temp;
}

template<class T>
void MyVector<T> :: alloc_new()
{
    maxsize=vsize*2;
    T *tmp=new T[maxsize];
    for(int i=0;i<vsize;i++)
        tmp[i]=array[i];
    delete[]array;
    array=tmp;
}

template<class T>
int MyVector<T> :: size()
{
    return vsize;
}
#endif // MYVECTOR_H_INCLUDED