Array类模板实现

Array类模板实现

---------------------------------------------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;
};

---------------------------------- 主函数（使用Array）------------------------------------------

// 各种类模板实现.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());
}