다항식 클래스 (class Polynomial) ​

#ifndef POLYNOMIAL_H
#define POLYNOMIAL_H

class Term
{
public:
 int exp;
 double coef;

 void Display(bool is_first_term);
};

class Polynomial
{
private:
 int max_exp;
 int capacity;

public:
 Term *termArray;
 int num_of_terms;

 Polynomial(int given_capacity);
 ~Polynomial();

 int NewTerm(double given_coef, int given_exp);

 Polynomial* Add(Polynomial* b);
 Polynomial* Mult(Polynomial* b);

 void Display();

 double Evaluate(double value);
};

#endif

#include <iostream>
#include "polynomial.h"
#include <cmath>

void Term::Display(bool is_first_term)
{
 if(coef == 0)
  return;

 if(coef > 0)
 {
  if(!is_first_term)
  {
   std::cout << " + " << coef;
  }
  else
  {
   std::cout << coef;
  }
 }

 if(coef < 0)
  std::cout << " - " << -coef;

 if(exp != 0)
  std::cout << "x";

 if(exp > 1)
  std::cout << "^";

 if(exp > 1)
  std::cout << exp;

}

Polynomial::Polynomial(int given_capacity)
{
 max_exp = -1;
 num_of_terms = 0;
 capacity = given_capacity;
 termArray = new Term[given_capacity];
}

Polynomial::~Polynomial()
{
 delete [] termArray;
}

int Polynomial::NewTerm(double given_coef, int given_exp)
{
 if(given_exp < 0)
  return -1;

 if(num_of_terms == capacity)
  return -1;

 for(int i=0;i<capacity;i++)
 {
  if(termArray[i].exp==given_exp)
   return -1;
 }

 termArray[num_of_terms].coef = given_coef;
 termArray[num_of_terms].exp = given_exp;

 num_of_terms++;

 if(max_exp < given_exp)
  max_exp = given_exp;

 return 0;
}

void Polynomial::Display()
{
 if(num_of_terms > 0)
 {
  int i,j;
  for(i=max_exp;i>=0;i--)
  {
   for(j=0;j<num_of_terms;j++)
   {
    if(termArray[j].exp==i)
     break;
   } 
   
   if(j != num_of_terms)
    termArray[j].Display(i==max_exp);

  }
 }
 std::cout << std::endl;
}

double Polynomial::Evaluate(double value)
{
 double result = 0;

 for(int i=0;i<num_of_terms;i++)
 {
  result += termArray[i].coef*pow(value,termArray[i].exp);
 }

 return result;
}

Polynomial* Polynomial::Add(Polynomial *b)
{
 Polynomial* result_poly;
 int num_of_term_in_result = num_of_terms + b->num_of_terms;
 int num_of_duplicate_exp=0;
 int i,j;

 for(i=0;i<num_of_terms;i++)
 {
  for(j=0;j<b->num_of_terms;j++)
  {
   if(termArray[i].exp == b->termArray[j].exp)
    num_of_duplicate_exp++;
  }
 }

 num_of_term_in_result -= num_of_duplicate_exp;

 result_poly = new Polynomial(num_of_term_in_result);

 for(i=0;i<num_of_terms;i++)
 {
  result_poly->NewTerm(termArray[i].coef,termArray[i].exp);
 }
 for(i=0;i<b->num_of_terms;i++)
 {
  for(j=0;j<result_poly->num_of_terms;j++)
  {
   if(result_poly->termArray[j].exp == b->termArray[i].exp)
   {
    result_poly->termArray[j].coef += b->termArray[i].coef;
    break;
   }
  }
  if(j == result_poly->num_of_terms)
  {
   result_poly->NewTerm(b->termArray[i].coef, b->termArray[i].exp);
  }
 }

 return result_poly;
}

Polynomial* Polynomial::Mult(Polynomial *b)
{
 Polynomial* result_poly;
 Polynomial* temp_poly;
 result_poly = new Polynomial(b->num_of_terms);

 int i,j;
 for(i=0;i<num_of_terms;i++)
 {
  temp_poly = new Polynomial(b->num_of_terms);

  for(j=0;j<b->num_of_terms;j++)
  {
   temp_poly->NewTerm(termArray[i].coef*b->termArray[j].coef, termArray[i].exp+b->termArray[j].exp);
  }
  result_poly = result_poly->Add(temp_poly);

  delete temp_poly;
 }

 return result_poly;
 
}