8-5(

C++多态性程序例子

#include <iostream.h>

class CharArray
{
public:
	CharArray(int l)
	{
		Length = l;
		Buff = new char[Length];
	}
	~CharArray() { delete Buff; }
	int GetLength() { return Length; }
	char & operator [](int i);
private:
	int Length;
	char * Buff;
};

char & CharArray::operator [](int i)
{
	static char ch = 0;
	if(i<Length&&i>=0)
		return Buff[i];
	else
	{
		cout<<"\nIndex out of range.";
		return ch;
	}
}

void main()
{
	int cnt;
	CharArray string1(6);
	char * string2 = "string";
	for(cnt=0; cnt<8; cnt++)
		string1[cnt] = string2[cnt];
	cout<<"\n";
	for(cnt=0; cnt<8; cnt++)
		cout<<string1[cnt];
	cout<<"\n";
	cout<<string1.GetLength()<<endl;
}