Question

分配：在这个作业中，您将开发一个C ++类来描述和操作多项式。

在标头中完成类声明，然后实现（在匹配的.cpp文件中）在头文件中声明的函数并测试它们以确保它们像宣传的那样工作。

提供的测试程序非常基础。您需要修改它并添加一些（2个或更多）测试以确保新类的所有方面都得到执行。

TestThePoly.cpp的示例结果：

(1) Testing cout << A: empty
(2) Testing cin >> A':
Enter the polynomial (integer degree then double coefficients):
3 -1 2.09 -5.3 -0.98
(3) Second look at A: -1x^(3) +2.09x^(2) -5.3x^(1) -0.98
(4) Testing Polynomial B(A): -1x^(3) +2.09x^(2) -5.3x^(1) -0.98
(5) Testing Polynomial C(2, clist)': +1x^(2) +4.5x^(1) +8
(6) Testing D = C: +1x^(2) +4.5x^(1) +8
(7) Testing A == B : TRUE
(8) Testing A == D : FALSE

我曾多次尝试过这项任务，但还没有弄清楚。我在网上看了一些我可以帮助我但没有找到任何东西的东西。大多数其他多项式类问题似乎涉及乘法等，并且至少比这更复杂。或者他们在某些方面比我更简单/做得与众不同。

这是头文件

// Polynomial.h

#ifndef POLYNOMIAL_H
#define POLYNOMIAL_H

#include <iostream>
using std::ostream;
using std::istream;




class Polynomial
{

  public:
    Polynomial();
    Polynomial( int dgr, const double* clist );
    Polynomial( const Polynomial& );
    ~Polynomial();

    int setDegree(int dgr); 
    int getDegree() const;   

    const Polynomial& operator=( const Polynomial& clist);
    bool operator==( const Polynomial& clist) const;




    void printPolynomial( int dgr, const double* clist );


    double operator[]( int index ) const;
    double& operator[]( int index );

  private:
      int    degree;
      double *coefficients; // list of coefficients


};

ostream& operator<<( ostream& , const Polynomial& );
istream& operator>>( istream& , Polynomial& );

#endif

这是源文件

// Polynomial.cpp


#include <iostream>
using std::istream;
using std::ostream;

using std::cerr;
using std::endl;

#include <cstdlib>
using std::exit;

#include "Polynomial.h"


Polynomial::Polynomial()
{
    degree        = 0;
    coefficients = 0;

}


Polynomial::Polynomial(int dgr, const double* clist)
{
     getDegree();

}

int Polynomial::getDegree() const
{
    return degree; 
}

Polynomial:: ~Polynomial()
{
    setDegree(0); 
}

int Polynomial::setDegree(int dgr)
{

    if( dgr <0 ) {
    cerr << "Error:  attempted to set a negative degree" << endl;
    exit(1);  
  } else {
    if( coefficients!=0 ) {
      delete [] coefficients;
      coefficients = 0;
      degree       = 0;
    }
    if( dgr !=0 ) {
      coefficients = new double [dgr];
      if( coefficients==0 ) {
        degree =0;
        cerr << "Warning:  unable to allocate enough space for list" << endl;
        exit(2); // this surely is reasonable.
      } else {
        degree=dgr;
      }
    }
  }
  return dgr;


}

//copy constructor 
Polynomial::Polynomial(const Polynomial& clist) : degree(0), coefficients(0)
{
  if( clist.getDegree()<=0 ) {
    setDegree(0);
  } else {
    setDegree(clist.getDegree());
    for (int i=0; i< degree ; i++) {
      coefficients[i]=clist.coefficients[i];
    }
  }
}


const Polynomial& Polynomial :: operator=(const Polynomial& clist) 
{
    if ( &clist==this ) 
    {
    cerr << "Warning:  attempt to copy Polynomial onto self" << endl;
    } 
    else {
    if( clist.getDegree()<=0 ) {
      setDegree(0);
    } else {
      setDegree(clist.getDegree());
      for (int i=0; i< degree ; i++) {
        coefficients[i] = clist.coefficients[i];
      }
    }
  }
  return *this;
}

bool  Polynomial::operator==(const Polynomial& clist) const
{
    bool result=true;
  if( degree!=clist.getDegree() ) {
    result=false;
  } else {
    for(int i=0; i< degree && result == true; i++) {
      result = coefficients[i]==clist.coefficients[i];
    }
  }
  return result;
}


double Polynomial::operator[]( int index ) const
{
  if( index<0 || index>= degree ) {
    cerr << "Attempt to access element outside index bounds" 
      << endl;
    exit(3); // Maybe not reasonable. 
  } else {
    return coefficients[index];
  }
}


double& Polynomial::operator[]( int index )
{
  if( index < 0 || index>= degree  ) {
    cerr << "Attempt to access element outside index bounds" 
      << endl;
    exit(4); 
  } else {
    return coefficients[index];
  }
}



ostream& operator<<( ostream& left, const Polynomial& right)
{
  if( right.getDegree() > 0 ) {
    left << endl;
    for (int i=0; i< right.getDegree(); i++ ) {
    for (int j = 0; j >= 0 ; j -- ){


      left << right[i] << "X^(" << j << ") " ;
  if (j > 0) 
  {     
      left << " + ";
  }

      }
    }
  } 
  else {
    cerr << "Warning:  Attempt to display empty List" << endl;
  }


  return left;
}


istream& operator>>( istream& left, Polynomial& right)
{
  int tmp;
  left >> tmp;
  if( tmp<=0 ) {
    cerr << "First value expected to be list size, > 0." << endl;
  } else {
    if( tmp!=right.getDegree() ) {
      right.setDegree(tmp);
    }
    for (int i=0; i<right.getDegree(); i++) {
      left >> right[i];
    }
  }
  return left;
}

这是测试/主文件

// Prog11.cpp

#include <iostream>
using std::cout;
using std::endl;
using std::cin;

#include "Polynomial.h"


int main()
{
  Polynomial A;
  cout << "(1) Testing `cout << A':  " << A << endl;

  cout << "(2) Testing `cin >> A':\n";
  cout << "Enter the polynomial (integer order then double    coefficients):\n\t ";
  cin >> A;
  cout << endl;
  cout << "(3) Second look at A:  " << A << endl;

  Polynomial B(A);
  cout << "(4) Testing `Polynomial B(A)':  " << B << endl;

  double clist[]={8, 4.5, 1};
  Polynomial C(2, clist);
  cout << "(5) Testing `Polynomial C(2, clist)':  " << C << endl;

  Polynomial D=C;
  cout << "(6) Testing D = C):  " << D << endl;

  cout << "(7) Testing A == B :  " << (A==B ? "TRUE" : "FALSE") << endl;
  cout << "(8) Testing A == D :  " << (A==D ? "TRUE" : "FALSE")<< endl;

  return 0;
}

C ++多项式类

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