C++中的异常处理(下)

 

 array.h

#ifndef _ARRAY_H_
#define _ARRAY_H_

#include <stdexcept>

using namespace std;

template
< typename T, int N >
class Array
{
    T m_array[N];
public:
    int length() const;
    bool set(int index, T value);
    bool get(int index, T& value);
    T& operator[] (int index);
    T operator[] (int index) const;
    virtual ~Array();
};

template
< typename T, int N >
int Array<T, N>::length() const
{
    return N;
}

template
< typename T, int N >
bool Array<T, N>::set(int index, T value)
{
    bool ret = (0 <= index) && (index < N);
    
    if( ret )
    {
        m_array[index] = value;
    }
    
    return ret;
}

template
< typename T, int N >
bool Array<T, N>::get(int index, T& value)
{
    bool ret = (0 <= index) && (index < N);
    
    if( ret )
    {
        value = m_array[index];
    }
    
    return ret;
}

template
< typename T, int N >
T& Array<T, N>::operator[] (int index)
{
    if( (0 <= index) && (index < N) )
    {
        return m_array[index];
    }
    else
    {
        throw out_of_range("T& Array<T, N>::operator[] (int index)");
    }
}

template
< typename T, int N >
T Array<T, N>::operator[] (int index) const
{
    if( (0 <= index) && (index < N) )
    {
        return m_array[index];
    }
    else
    {
        throw out_of_range("T Array<T, N>::operator[] (int index) const");
    }
}

template
< typename T, int N >
Array<T, N>::~Array()
{

}

#endif

HeapArray.h

#ifndef _HEAPARRAY_H_
#define _HEAPARRAY_H_

#include <stdexcept>

using namespace std;

template
< typename T >
class HeapArray
{
private:
    int m_length;
    T* m_pointer;
    
    HeapArray(int len);
    HeapArray(const HeapArray<T>& obj);
    bool construct();
public:
    static HeapArray<T>* NewInstance(int length); 
    int length() const;
    bool get(int index, T& value);
    bool set(int index ,T value);
    T& operator [] (int index);
    T operator [] (int index) const;
    HeapArray<T>& self();
    const HeapArray<T>& self() const;
    ~HeapArray();
};

template
< typename T >
HeapArray<T>::HeapArray(int len)
{
    m_length = len;
}

template
< typename T >
bool HeapArray<T>::construct()
{   
    m_pointer = new T[m_length];
    
    return m_pointer != NULL;
}

template
< typename T >
HeapArray<T>* HeapArray<T>::NewInstance(int length) 
{
    HeapArray<T>* ret = new HeapArray<T>(length);
    
    if( !(ret && ret->construct()) ) 
    {
        delete ret;
        ret = 0;
    }
        
    return ret;
}

template
< typename T >
int HeapArray<T>::length() const
{
    return m_length;
}

template
< typename T >
bool HeapArray<T>::get(int index, T& value)
{
    bool ret = (0 <= index) && (index < length());
    
    if( ret )
    {
        value = m_pointer[index];
    }
    
    return ret;
}

template
< typename T >
bool HeapArray<T>::set(int index, T value)
{
    bool ret = (0 <= index) && (index < length());
    
    if( ret )
    {
        m_pointer[index] = value;
    }
    
    return ret;
}

template
< typename T >
T& HeapArray<T>::operator [] (int index)
{
    if( (0 <= index) && (index < length()) )
    {
        return m_pointer[index];
    }
    else
    {
        throw out_of_range("T& HeapArray<T>::operator [] (int index)");
    }
}

template
< typename T >
T HeapArray<T>::operator [] (int index) const
{
    if( (0 <= index) && (index < length()) )
    {
        return m_pointer[index];
    }
    else
    {
        throw out_of_range("T HeapArray<T>::operator [] (int index) const");
    }
}

template
< typename T >
HeapArray<T>& HeapArray<T>::self()
{
    return *this;
}

template
< typename T >
const HeapArray<T>& HeapArray<T>::self() const
{
    return *this;
}

template
< typename T >
HeapArray<T>::~HeapArray()
{
    delete[]m_pointer;
}


#endif

#include <iostream>
#include <string>
#include "Array.h"
#include "HeapArray.h"

using namespace std;

void TestArray()
{
    Array<int, 5> a;
    
    for(int i=0; i<a.length(); i++)
    {
        a[i] = i;
    }
        
    for(int i=0; i<a.length(); i++)
    {
        cout << a[i] << endl;
    }
}

void TestHeapArray()
{
    HeapArray<double>* pa = HeapArray<double>::NewInstance(5);
    
    if( pa != NULL )
    {
        HeapArray<double>& array = pa->self();
        
        for(int i=0; i<array.length(); i++)
        {
            array[i] = i;
        }
            
        for(int i=0; i<array.length(); i++)
        {
            cout << array[i] << endl;
        }
    }
    
    delete pa;
}

int main(int argc, char *argv[])
{
    
    try
    {
        TestArray();
        
        cout << endl;
        
        TestHeapArray();
    }
    catch(...)
    {
        cout << "Exception" << endl;
    }
    
    return 0;
}