Array類模板實現

Array類模板實現

---------------------------------------------Array.h------------------------------------------------------ 

#include<string>
using namespace std;

template<class DataType>
class Array
{
public:
 /*
 Array(int szie);
 inline DataType &operator[](int index);
 void changeSize(int newSize);
 inline int length() const;
 string err() const;
 */
 Array(int size)
 {
  if(size<1)
  {
   capacity = 1;
   errorCode = 1;
  }
  else
  {
   capacity = size;
   errorCode = 0;
  }
  elements = new DataType[capacity];
 }

 inline DataType &operator [](int index)
 {
#ifdef DEBUG_ARRAY
  if(index<0||index>=capacity)
  {
   errorCode |=2;
   return dud;
  }
#endif
  return elements[index];
 }

 void changeSize(int newSize)
 {
  if(newSize<1)
  {
   errorCode |=4;
   return;
  }
  DataType *newArray = new DataType[newSize];
  int limit = (newSize>capacity)?capacity:newSize;
  for(int i = 0;i < limit;i++)
   newArray[i] = elements[i];
  delete[] elements;
  elements = newArray;
  capacity = newSize;
 }

 inline int length() const
 {
  return capacity;
 }

 string err() const
 {
  if(errorCode==0)
   return "No error.\n";

  string errorMessage = "";
  if(errorCode&1)
  {
   errorMessage +="Nonpositive size passed into constructor,so\n";
   errorMessage +="the capacity was set to 1 by default.\n";
  }
  if(errorCode&2)
  {
   errorMessage +="Index out of range.\n";
  }
  if(errorCode&4)
  {
   errorMessage += "Nonpositive size passed into changeSize,so\n";
   errorMessage += "the size of the array was not change.\n";
  }
  return errorMessage;
 }
private:
 DataType *elements;
 int capacity;
 DataType dud;
 int errorCode;
};

---------------------------------- 主函數（使用Array）------------------------------------------

// 各種類模板實現.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include<iostream>
#include "Array.h"
#define DEBUG_ARRAY
using namespace std;

void getElements( Array<int> &numbers);

float calcAverage( Array<int> avnums);

int _tmain(int argc, _TCHAR* argv[])
{
 Array<int> nums(2);
 getElements(nums);
 float average = calcAverage(nums);
 cout<<"The average is:"<<average<<endl;
 cout<<endl;
 system("pause");
 return 0;
}

void getElements(Array<int> &numbers)
{
 int i = 0;
 cout<<"Enter a positive integer:";
 cin >> numbers[i];
 while(numbers[i] !=-1)
 {
  i++;
  if(i == numbers.length())
   numbers.changeSize(2*i);
  cout<<"Enter a positive integer(enter -1 to end):";
  cin>>numbers[i];
 }
 numbers.changeSize(i);

 cout<<"getElemens:"<<numbers.err()<<endl;

}

float calcAverage(Array<int> avnums)
{
 int sum = 0;
 for(int i=0;i<avnums.length();i++)
  sum += avnums[i];
 cout<<"calcAverage:"<<avnums.err()<<endl;
 return sum/(float)(avnums.length());
}