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March 5th, 2011, 11:56 AM
#1
How to access the size of another class
Hello, I'm having trouble with multiple parts in my polynomial program. First of all, I can't seem to find a way to access the mySize variable from the Polynomial class, also, I'm not quite sure how to combine the liketerms, and finally if you could give me some tips for the multiplication function in Polynomial class. Any help would be appreciated.
polynomial.cpp
Code:
#include <cassert>
using namespace std;
#include "Polynomial.h"
/*----------------------------------------------------------------------
Member and friend functions for Monomial.
-----------------------------------------------------------------------*/
Monomial operator+(Monomial& a, Monomial& b) {
Monomial res;
for(int i = 0; i < mySize; i++){ // Attempting to access mySize from here and combine liketerms
if(a.exp == b.exp){
res.coef = a.coef + b.coef;
res.exp = a.exp;
}
else if(a.exp != b.exp){
res.coef = a.coef;
res.exp = a.exp;
}
else if(b.exp != a.exp){
res.coef = b.coef;
res.exp = b.exp;
}
}
return res;
}
Monomial operator-(Monomial& a, Monomial& b) {
Monomial res;
for(int i = 0; i < mySize; i++){ // Attempting to access mySize from here and combine liketerms
if(a.exp == b.exp){
res.coef = a.coef - b.coef;
res.exp = a.exp;
}
else if(a.exp != b.exp){
res.coef = a.coef;
res.exp = a.exp;
}
else if(b.exp != a.exp){
res.coef = b.coef;
res.exp = b.exp;
}
}
return res;
}
Monomial operator*(Monomial& a, Monomial& b) {
Monomial res;
res.coef = a.coef * b.coef;
res.exp = a.exp + b.exp;
return res;
}
ostream & operator<< (ostream & out, const Monomial & mono)
{
out << mono.coef ;
if (mono.exp > 0) out << "x^" << mono.exp;
return out;
}
/*----------------------------------------------------------------------
Member and friend functions for Polinomial.
-----------------------------------------------------------------------*/
Polynomial::Polynomial()
: mySize(0)
{}
bool Polynomial::empty() const
{
return mySize == 0;
}
void Polynomial::display(ostream & out) const
{
for (int i = mySize-1; i >= 0 ; i--) {
if (i != mySize-1) out << " + ";
out << myArray[i];
}
}
ostream & operator<< (ostream & out, const Polynomial & aList)
{
aList.display(out);
return out;
}
void Polynomial::insert(ElementType item, int pos)
{
if (mySize == CAPACITY)
{
cerr << "*** No space for list element -- terminating "
"execution ***\n";
exit(1);
}
if (pos < 0 || pos > mySize)
{
cerr << "*** Illegal location to insert -- " << pos
<< ". List unchanged. ***\n";
return;
}
// First shift array elements right to make room for item
for(int i = mySize; i > pos; i--)
myArray[i] = myArray[i - 1];
// Now insert item at position pos and increase list size
myArray[pos] = item;
mySize++;
}
void Polynomial::erase(int pos)
{
if (mySize == 0)
{
cerr << "*** List is empty ***\n";
return;
}
if (pos < 0 || pos >= mySize)
{
cerr << "Illegal location to delete -- " << pos
<< ". List unchanged. ***\n";
return;
}
// Shift array elements left to close the gap
for(int i = pos; i < mySize; i++)
myArray[i] = myArray[i + 1];
// Decrease list size
mySize--;
}
Polynomial operator+(Polynomial &p1, Polynomial &p2){
Polynomial res;
int i = 0;
if (p1.mySize > p2.mySize){
res.mySize = p1.mySize;
}else{
res.mySize = p2.mySize;
}
for(i = 0; i < res.mySize; i++){
res.myArray[i] = p1.myArray[i] + p2.myArray[i];
}
return res;
}
Polynomial operator*(Polynomial &p1, Polynomial &p2){ // Multiplication does not work properly
Polynomial res;
int i = 0;
if (p1.mySize > p2.mySize){
res.mySize = p1.mySize;
}
else{
res.mySize = p2.mySize;
}
/*for(i = 0; i < res.mySize; i++){
res.myArray[i] = p1.myArray[i] * p2.myArray[i];
}*/
for (i = 0; i < res.mySize; i++){
for (int j=0; j < res.mySize; j++){
res.myArray[i+j] = (p1.myArray[i]*p2.myArray[j]) ;
}
}
return res;
}
polynomial.h
Code:
#include <iostream>
#ifndef PNOM
#define PNOM
const int CAPACITY = 1024;
class Monomial {
protected:
int coef;
int exp;
// int size;
public:
Monomial(){};
/*----------------------------------------------------------------------
Construct a Monomial object.
Precondition: None
Postcondition: An empty Monomial object has been constructed..
-----------------------------------------------------------------------*/
Monomial(int c,int p) { coef = c; exp = p;};
friend Monomial operator+ (Monomial&, Monomial&);
friend Monomial operator- (Monomial&, Monomial&);
friend Monomial operator* (Monomial&, Monomial&);
friend class Polynomial;
int getExponent() {return exp;}
int getCoefficient() {return coef;}
/*----------------------------------------------------------------------
Construct a Monomial object with specified coeffient and exponent.
Precondition: None
Postcondition: A Monomial object has been constructed with the
specified coeffient and exponent.
-----------------------------------------------------------------------*/
friend ostream & operator<< (ostream & out, const Monomial & mono);
/*----------------------------------------------------------------------
Overloading the OUTPUT operator for Monomials.
Precondition: None.
Postcondition: The coefficient and exponent (if != 0) of the monomial are
displayed in the default output device.
-----------------------------------------------------------------------*/
};
typedef Monomial ElementType;
class Polynomial
{
public:
friend class Monomial;
Polynomial();
/*----------------------------------------------------------------------
Construct a List object.
Precondition: None
Postcondition: An empty List object has been constructed; mySize is 0.
-----------------------------------------------------------------------*/
/***** empty operation *****/
bool empty() const;
/*----------------------------------------------------------------------
Check if a list is empty.
Precondition: None
Postcondition: true is returned if the list is empty, false if not.
-----------------------------------------------------------------------*/
/***** insert and erase *****/
void insert(ElementType item, int pos);
/*----------------------------------------------------------------------
Insert a value into the list at a given position.
Precondition: item is the value to be inserted; there is room in
the array (mySize < CAPACITY); and the position satisfies
0 <= pos <= mySize.
Postcondition: item has been inserted into the list at the position
determined by pos (provided there is room and pos is a legal
position).
-----------------------------------------------------------------------*/
void erase(int pos);
/*----------------------------------------------------------------------
Remove a value from the list at a given position.
Precondition: The list is not empty and the position satisfies
0 <= pos < mySize.
Postcondition: element at the position determined by pos has been
removed (provided pos is a legal position).
----------------------------------------------------------------------*/
friend Polynomial operator+(Polynomial &, Polynomial &);
friend Polynomial operator*(Polynomial &, Polynomial &);
/***** output *****/
void display(ostream & out) const;
protected:
int mySize; // current size of list stored in myArray
ElementType myArray[CAPACITY]; // array to store the Monomials
}; //--- end of List class
//------ Prototype of output operator
ostream & operator<< (ostream & out, const Polynomial & p);
#endif
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