polynomial.cpp

实现多项式运算的程序,该程序充分考虑了计算中可能遇到的各种问题

#ifndef  _MY_POLY1_
#define  _MY_POLY1_

#define  safedelete(p)  if(p) { delete p; p = NULL; }

#include "Polynomial.h"
#include <math.h>

//建立一个空表
CPolynomial::CPolynomial( )
{
   m_pHead = new CTerm;
   m_pHead->SetNext( m_pHead );
   m_pHead->SetPrev( m_pHead );	   
}

CPolynomial::CPolynomial(CTerm *Know)
{
	m_pHead = new CTerm;
	m_pHead->SetNext( m_pHead );
    m_pHead->SetPrev( m_pHead );

	CTerm *m, *n,*next;
	m = Know->GetNext();
	next = m_pHead;
	while ( m != Know )
	{
		n = new CTerm( m->GetDegree(), m->GetCoef(), m_pHead );
		n->SetPrev( next );
		next->SetNext( n );
		m_pHead->SetPrev( n );
		next = n;
		m = ( m->GetNext() );
	}
	

}

//析构函数
CPolynomial::~CPolynomial( )
{
	Empty();
    safedelete( m_pHead );
}

int CPolynomial::Empty()
{
	CTerm	*p;
	if ( m_pHead->GetNext() != NULL )
	{
		while ( m_pHead->GetNext() != m_pHead )
		{
			p = m_pHead->GetNext();
			m_pHead->SetNext( p->GetNext() );
			safedelete(p);
		}
		
		
	}
	m_pHead->SetPrev(m_pHead);
	return 1;

}

int CPolynomial::Length( )
{
	CTerm *p = m_pHead->GetNext();
	int  len = 0;
	while ( p != m_pHead )
	{
		len++;
		p = p->GetNext();
	}
	return len;
}

CTerm  *CPolynomial::GetPoint(int val )
{
	if ( val<0 || val>=Length() )
	{
		cout<<"error of the length of val"<<endl;
	}

	CTerm *p = m_pHead;
		
	for( int i=0; i<=val; i++)
	{
		p = p->GetNext();
	}
	return p;
}


int CPolynomial::PushBack( int Degree, double Coef )
{
	CTerm *p = new CTerm( Degree, Coef, m_pHead );
    
	CTerm *next;
	next = m_pHead;
	while ( next->GetNext() != m_pHead )
	{
		next = next->GetNext();
	}

	p->SetPrev( next );
	next->SetNext( p );
	m_pHead->SetPrev( p );
	return 1;
}

int CPolynomial::Insert(CTerm *p, int Degree, double Ceof )
{
	//to do here....
	if ( p!= NULL)
	{
		CTerm *q = new CTerm( Degree, Ceof, p );

		q->SetPrev( p->GetPrev() );
		p->GetPrev()->SetNext( q );
		p->SetPrev( q );
	}
	return 1;
}

int CPolynomial::Delete( CTerm *p )
{
	if ( p != NULL)
	{
		p->GetPrev()->SetNext( p->GetNext() );
		p->GetNext()->SetPrev( p->GetPrev() );
		safedelete( p );
	}
	return 1;

}

int CPolynomial::GetDegree(int val )
{
	//to do here...
	return 1;
}

int CPolynomial::Print()
{
	cout<<endl;
	CTerm *p;
	p = m_pHead->GetNext();
	while ( p != m_pHead )
	{
		cout<<p->GetDegree()<<"  "<<p->GetCoef()<<endl;
		p = p->GetNext();
	}
	cout<<"ok"<<endl;
	return 1;
}

int  CPolynomial::Read1( )
{
	ifstream  istrm( "p1.txt" );

	if ( !istrm.good() )
	{
		cout<<"cann't open the file! "<<endl;
	}
	//read the file
	char p;
	int  size;
	istrm>>p>>size;
    //read the degree and the ceof
	int degree, coef;
	CTerm  *m, *q;
	q = m_pHead->GetNext();

	istrm>>degree>>coef;
	//cout<<degree<<coef<<"shen"<<endl;
	PushBack( degree, coef );
		
	for ( int i=0; i<size-1; i++)
	{
		istrm>>degree>>coef;
        while (q->GetDegree() <= degree && q != m_pHead )
        {
			q = q->GetNext();
        }
		if ( q->GetPrev()->GetDegree() != degree)
		{
			Insert( q, degree, coef );
		}
		else
		{
			m = ( q->GetPrev() );
			m->SetCoef( m->GetCoef() + coef);
		}
        q = m_pHead->GetNext();
	}
	istrm.close();
	return 1;
}

int CPolynomial::Read2( )
{
	//to do here...
    ifstream  istrm( "p2.txt" );
	
	if ( !istrm.good() )
	{
		cout<<"cann't open the file! "<<endl;
	}
	//read the file
	char p;
	int  size;
	istrm>>p>>size;
    //read the degree and the ceof
	int degree, coef;
	CTerm  *m, *q;
	q = m_pHead->GetNext();
	
	istrm>>degree>>coef;
	PushBack( degree, coef );
	
	for ( int i=0; i<size-1; i++)
	{
		istrm>>degree>>coef;
        while (q->GetDegree() <= degree && q != m_pHead )
        {
			q = q->GetNext();
        }
		if ( q->GetPrev()->GetDegree() != degree)
		{
			Insert( q, degree, coef );
		}
		else
		{
			m = ( q->GetPrev() );
			m->SetCoef( m->GetCoef() + coef);
		}
        q = m_pHead->GetNext();
	}
	istrm.close();
	return 1;
}

//用成员函数重载赋值运算符
CPolynomial&  CPolynomial::operator= (const CPolynomial &p )
{
	Empty();
	CTerm *m, *n,*next;
	m = p.m_pHead->GetNext();
	next = m_pHead;
	while ( m != p.m_pHead )
	{
		n = new CTerm( m->GetDegree(), m->GetCoef(), m_pHead );
		n->SetPrev( next );
		next->SetNext( n );
		m_pHead->SetPrev( n );
		next = n;
		m = ( m->GetNext() );
	}
	return *this;
    
}

//重载加号运算符
CPolynomial  operator+ ( const CPolynomial &p1, const CPolynomial &p2)
{
	CPolynomial  Result;
    CTerm  *next1, *next2;
	next1 = p1.m_pHead->GetNext();
	next2 = p2.m_pHead->GetNext();
	int degree1,degree2;
	
	while ( next1!=p1.m_pHead && next2 != p2.m_pHead )
	{   
		degree1 = next1->GetDegree();
	    degree2 = next2->GetDegree();
		if ( degree1 < degree2 )
		{
            Result.PushBack(next1->GetDegree(), next1->GetCoef() );
			next1 = next1->GetNext();
		}
		else if( degree1 == degree2 )
		{
			Result.PushBack(next1->GetDegree(), next2->GetCoef()+next1->GetCoef() );
			next1 = next1->GetNext();
			next2 = next2->GetNext();			
		}
		else
		{
			Result.PushBack(next2->GetDegree(), next2->GetCoef() );
			next2 = next2->GetNext();
		}
		
	}
	while (next1 != p1.m_pHead)
	{
		Result.PushBack(next1->GetDegree(),next1->GetCoef());
		next1 = next1->GetNext();
	}
	while (next2 != p2.m_pHead )
	{
		Result.PushBack(next2->GetDegree(),next2->GetCoef());
		next2 = next2->GetNext();
	}
	return  CPolynomial( Result.m_pHead );

}
//重载减好运算符
CPolynomial  operator- ( const CPolynomial &p1, const CPolynomial &p2)
{
	CPolynomial  Result;
    CTerm  *next1, *next2;
	next1 = p1.m_pHead->GetNext();
	next2 = p2.m_pHead->GetNext();
	int degree1,degree2;
	
	while ( next1!=p1.m_pHead && next2 != p2.m_pHead )
	{   
		degree1 = next1->GetDegree();
		degree2 = next2->GetDegree();
		if ( degree1 < degree2 )
		{
            Result.PushBack(next1->GetDegree(), next1->GetCoef() );
			next1 = next1->GetNext();
		}
		else if( degree1 == degree2 )
		{
			if ( (next2->GetCoef()-next1->GetCoef()) != 0 )
			{
				Result.PushBack(next1->GetDegree(), next1->GetCoef()-next2->GetCoef() );
				
			}
			next1 = next1->GetNext();
			next2 = next2->GetNext();
		}
		else
		{
			Result.PushBack(next2->GetDegree(), -next2->GetCoef() );
			next2 = next2->GetNext();
		}
		
	}
	while (next1 != p1.m_pHead)
	{
		Result.PushBack(next1->GetDegree(),next1->GetCoef());
		next1 = next1->GetNext();
	}
	while (next2 != p2.m_pHead )
	{
		Result.PushBack(next2->GetDegree(),-next2->GetCoef());
		next2 = next2->GetNext();
	}
	return  CPolynomial( Result.m_pHead );
}

CPolynomial  operator* ( const CPolynomial &p1, const CPolynomial &p2)
{
	//ji ben suan fa
	CPolynomial Temp, Result;
	CTerm *next1,*next2;
	Temp = p2;
	next1 = p1.m_pHead->GetNext();
	next2 = Temp.m_pHead->GetNext();
	while ( next1!= p1.m_pHead )
	{
		while ( next2 != Temp.m_pHead )
		{
			next2->SetDegree(next1->GetDegree() + next2->GetDegree() );
			next2->SetCoef(next1->GetCoef() * next2->GetCoef());
		    next2 = next2->GetNext();
		}

		Result = Result + Temp;
		next1 = next1->GetNext();
        Temp = p2;
		next2 = Temp.GetHead()->GetNext();
	}
	return  CPolynomial( Result.m_pHead );
}

#endif