myarray.h

把数据结构里面的数组类实现,可以方便大家用来学习。

#include "stdafx.h"
#include <iostream>
using namespace std;

template <class type>
class Array{
private:
	type *arrayelems;
	int size;
public:
	Array(int sz=50);
	Array(const Array <type> &x);
	~Array(){delete []arrayelems;};
	Array<type> &operator = (const Array <type> &arr);
	type &operator [](int n);
	int Length(){return size;}
	void resize(int sz);
};

template <class type>
Array<type>::Array(int sz = 50):arrayelems(NULL),size(sz){
	arrayelems=new type[sz];
	if(arrayelems==NULL)
	{
		cerr<<"分配失败"<<endl;
		exit(1);
	}
}

template <class type>
Array<type>::Array(const Array<type> &x){
	delete []arrayelems;
	size=x.size;
	arrayelems=new type[size];
	if(arrayelems==NULL)
	{
		cerr<<"分配失败"<<endl;
		size=0;
		exit(1);
	}
	memcpy(arrayelems,x.arrayelems,size);
}

template <class type>
Array<type> &Array<type>::operator =(const Array<type> &arr)
{
	if(arrayelems==arr.arrayelems)
		return *this;//self-assignment
	delete []arrayelems;
	size=arr.size;
	arrayelems=new type[size];
	if(arrayelems==NULL)
	{
		cerr<<"分配失败"<<endl;
		size=0;
		exit(1);
	}
	/*memcpy(arrayelems,arr.arrayelems,size);
	return *this;*/
	type * p1=arrayelems;
	type * p2=arr.arrayelems;
	int n=size;
	while(n--) *p1++=*p2++;
	return *this;
}

template <class type>
type & Array<type>::operator [](int n)
{
	if(n>size-1||n<0)
	{
		cerr<<"越界"<<endl;
		exit(1);
	}
	return arrayelems[n];
}

template <class type>
void Array<type>::resize(int sz)
{
	type * p1;
	type * p2;
	if(sz<=0)
	{
		cerr<<"数组长度非法"<<endl;
		exit(1);
	}
	if(sz!=size)
	{
		type *newarr=new type[sz];
		if(newarr==NULL)
		{
			cerr<<"分配失败"<<endl;
			exit(1);
		}
		if(sz>=size)
		{
			//memcpy(newarr,arrayelems,size);
		    p1=arrayelems;
		    p2=newarr;
			int n=size;
			while(n--) *p2++=*p1++;

		}
		else
		{
			//memcpy(newarr,arrayelems,sz);
			p1=arrayelems;
			p2=newarr;
			int n=sz;
			while(n--) *p2++=*p1++;
			
		}
		delete []arrayelems;
		arrayelems=NULL;
		arrayelems=new type[sz];
		size=sz;
		if(arrayelems==NULL)
		{
			cerr<<"分配失败"<<endl;
			exit(1);
		}
		//memecpy(arrayelems,newarr,size);
			p1=arrayelems;
			p2=newarr;
			int n=sz;
			while(n--) *p1++=*p2++;
			delete []newarr;
	}
}