hw7-2

#include "function.h"

using namespace std;
Polynomial::Polynomial()
{
    greatestPower=0;
    coefficients[0]=0;
}
Polynomial::Polynomial(const int N, const int C[51])
{
    greatestPower=N;
    for(int i=N; i>=0; i--)
    {
        coefficients[i]=C[i];
    }
}
Polynomial Polynomial::add( const Polynomial b) const
{
    Polynomial c;
    int a=(greatestPower>b.greatestPower)?greatestPower:b.greatestPower;
    c.greatestPower =a;
    for(int i=a; i>=0; i--)
    {
        c.coefficients[i]=coefficients[i]+b.coefficients[i];
    }
    return c;
} // add function
Polynomial Polynomial::subtract( const Polynomial b) const
{
    Polynomial c;
    int a=(greatestPower>b.greatestPower)?greatestPower:b.greatestPower;
    c.greatestPower =a;
    for(int i=a; i>=0; i--)
    {
        c.coefficients[i]=coefficients[i]-b.coefficients[i];
    }
    return c;
} // subtract function
Polynomial Polynomial::multiplication( const Polynomial b) const
{
    Polynomial c;
    c.greatestPower = greatestPower + b.greatestPower;
    // clear the coefficients array in Polynomial c
    for (int i=0; i<=c.greatestPower; ++i) {
        c.coefficients[i] = 0;
    }
    for(int i=greatestPower; i>=0; i--)
    {
        for(int j=b.greatestPower; j>=0; j--)
        {
            c.coefficients[i+j]+=coefficients[i]*b.coefficients[j];
        }
    }
    return c;
} // multiplication function
void Polynomial::output() const
{
    for(int i=this->greatestPower; i>0; i--)
    {
        cout<< this->coefficients[i] << " ";
    }
    cout << this->coefficients[0] << endl;
}