C++用类实现一元多项式加减乘

刚刚学C++

正在慢慢的体会类的思想，面向对象的思想。。。

感觉用动态数组要比链表麻烦很多。。也许是我水平有限吧~

接口文件poly.h

#ifndef POLY_H
#define POLY_H
#include
#include
#include
using namespace std;
typedef int* intptr;
class poly
{
public:
poly();
poly(int a);
poly(const poly& p);
~poly();
void creat();
friend poly operator +(const poly& p1,const poly& p2);
friend poly operator -(const poly& p1,const poly& p2);
friend poly operator *(const poly& p1,const poly& p2);
poly& operator =(const poly& p);
friend ostream& operator <<(ostream& outs,const poly& p);
private:
intptr polyomial;
int len;
};
#endif

多项式类的实现poly.cpp

#include
#include "poly.h"
#include
using namespace std;

poly::poly()
{ polyomial=NULL;
len=0;
}

poly::poly(int a)
{len=1;
polyomial=new int[1];
polyomial[0]=a;
}

poly::poly(const poly& p)
{ len=p.len;
polyomial=new int[len];
for(int i=0;i polyomial[i]=p.polyomial[i];

}

poly::~poly()
{
delete [] polyomial;
}

void poly::creat()
{ vector v1,v2;
int c1,c2;
cin>>c1>>c2;
while(c1!=0)
{
v1.push_back(c1);
v2.push_back(c2);
cin>>c1>>c2;
}

int max=v2[0];
for(int i=1;i if(max

//int max=v2[v2.size()-1];

polyomial=new int[max+1];
len=max+1;
for(int z=0;z polyomial[z]=0;
for(int i=0;i {
for(int j=0;j {if(i==v2[j])polyomial[i]=v1[j];

}
}

}

poly operator +(const poly& p1,const poly& p2)
{ poly a;
if(p1.len>p2.len)
{ a.polyomial=new int[p1.len];
for(int i=0;i a.polyomial[i]=p1.polyomial[i]+p2.polyomial[i];
for(int i=p2.len;i a.polyomial[i]=p1.polyomial[i];
a.len=p1.len;
}
else
{ a.polyomial=new int[p2.len];
for(int i=0;i a.polyomial[i]=p1.polyomial[i]+p2.polyomial[i];
for(int i=p1.len;i a.polyomial[i]=p1.polyomial[i];
a.len=p2.len;
}
return a;
}

poly operator -(const poly& p1,const poly& p2)
{ poly a;
if(p1.len>p2.len)
{ a.polyomial=new int[p1.len];
for(int i=0;i a.polyomial[i]=p1.polyomial[i]-p2.polyomial[i];
for(int i=p2.len;i a.polyomial[i]=p1.polyomial[i];
a.len=p1.len;
}
else if(p1.len { a.polyomial=new int[p2.len];
for(int i=0;i a.polyomial[i]=p1.polyomial[i]-p2.polyomial[i];
for(int i=p1.len;i a.polyomial[i]=-p2.polyomial[i];
a.len=p2.len;
}
else
{
a.polyomial=new int[p1.len];
for(int i=0;i a.polyomial[i]=p1.polyomial[i]-p2.polyomial[i];
a.len=p1.len;
}
return a;
}

poly operator *(const poly& p1,const poly& p2)
{
poly a;

a.polyomial=new int[p1.len+p2.len-1];

a.len=p1.len+p2.len-1;
for(int i=0;i a.polyomial[i]=0;
for(int i=0;i {
for(int j=0;j {
if(0==i){ a.polyomial[i+j]=p2.polyomial[i]*p1.polyomial[j];}
else { a.polyomial[i+j]=a.polyomial[i+j]+p2.polyomial[i]*p1.polyomial[j];}
}
}
return a;
}

poly& poly:: operator =(const poly& p)
{ len=p.len;
polyomial=new int[len];
for(int i=0;i polyomial[i]=p.polyomial[i];
return (*this);
}

ostream& operator <<(ostream& outs,const poly& p)
{int n=0;
for(int i=0;i if(p.polyomial[i]!=0)
{ n++;
if(1==n)
{
if(0==i)outs< else outs< }
else
{

if(0==i)outs< else if(p.polyomial[i]>0)outs<<"+"< else outs< }
}
return outs;
}