Lecture19code-myvector.txt

/*
 *  File: myvector.h
 *  ----------------
 *
 *  Created by Julie Zelenski on 2/22/08.
 *
 */
#ifndef _myvector_h
#define _myvector_h

#include "genlib.h"
#include "disallowcopy.h"

template <typename ElemType>
class MyVector
{
 public:
	MyVector();
	~MyVector();
	
	int size();
	void add(ElemType s);
	ElemType getAt(int index);
	void setAt(int index, ElemType s);
	void insertAt(int index, ElemType e);
	
  private:
	ElemType *arr;
	int numUsed, numAllocated;
	void doubleCapacity();
	// this prevents default memberwise copy of Vector objects
	DISALLOW_COPYING(MyVector);
};

// #include .cpp because of template (quiirky)
#include "myvector.cpp"


#endif

/*
 *  File: myvector.cpp
 *  ------------------
 *
 *  Created by Julie Zelenski on 2/22/08.
 *
 */

#include "myvector.h"

template <typename ElemType>
MyVector<ElemType>::MyVector()
{	
	arr = new ElemType[2];
	numAllocated = 2;
	numUsed = 0;
}

template <typename ElemType>
MyVector<ElemType>::~MyVector()
{
	delete[] arr;
}


template <typename ElemType>
int MyVector<ElemType>::size()
{
	return numUsed;
}

template <typename ElemType>
ElemType MyVector<ElemType>::getAt(int index)
{
	if (index < 0 || index >= size())
		Error("Out of bounds");
	return arr[index];
}

template <typename ElemType>
void MyVector<ElemType>::setAt(int index, ElemType e)
{
	if (index < 0 || index >= size())
		Error("Out of bounds");
	arr[index] = e;
}

template <typename ElemType>
void MyVector<ElemType>::insertAt(int index, ElemType e)
{
	if (index < 0 || index >= size())
		Error("Out of bounds");
	if (numUsed == numAllocated)
		doubleCapacity();
	for (int i = size()-1; i >= index; i--)
		arr[i+1] = arr[i];
	arr[index] = e;
	numUsed++;
}



template <typename ElemType>
void MyVector<ElemType>::add(ElemType s)
{
	if (numUsed == numAllocated)
		doubleCapacity();
	arr[numUsed++] = s;
}

template <typename ElemType>
void MyVector<ElemType>::doubleCapacity()
{
	ElemType *bigger = new ElemType[numAllocated*2];
	for (int i = 0; i < numUsed; i++)
		bigger[i] = arr[i];
	delete[] arr;
	arr = bigger;
	numAllocated*= 2;
}