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poly0.cxx
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poly0.cxx
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// Sean Shelton, Patrick Vidican
// Jan 24 2016
// poly0.cxx
#include <iostream>
#include <cassert>
#include "poly0.h"
#include <cmath>
#include <climits>
namespace main_savitch_3 {
//constructor
polynomial::polynomial(double c, unsigned int exponent){
assert(exponent <= MAX_EX);
if (c == 0) { current_degree = 0; }
else { current_degree = exponent; }
for (int i=MAX_EX; i>current_degree; i--){
coef[i] = 0;
}
coef[current_degree] = c;
for (int j=0; j<current_degree; j++){
coef[j] = 0;
}
}
const unsigned int CAPACITY = 30;
const unsigned int MAX_EX = CAPACITY - 1;
//modification members
void polynomial::add_to_coef(double amount, unsigned int exponent){
assert(exponent <= MAX_EX);
//if the amount passed here is the negative version of what is already
//in coef[exponent] then the current degree goes down by 1
coef[exponent] += amount;
for (int i = 0; i <= MAX_EX; i++) {
if ( coef[i] != 0){
current_degree = i;
}
}
}
void polynomial::assign_coef(double coefficient, unsigned int exponent){
assert(exponent <= MAX_EX);
coef[exponent] = coefficient;
current_degree = exponent;
// the segfault was because the << wasn't implemented yet but now
// we have something printing woohoo
for (int i = 0; i <= MAX_EX; i++) {
if ( coef[i] != 0){
current_degree = i;
}
}
}
void polynomial::clear(){
for (int i=0; i<=degree(); i++){
coef[i] = 0;
}
current_degree = 0;
}
double polynomial::coefficient(unsigned int exponent) const{
if (exponent > MAX_EX) { return 0; }
else{ return( coef[exponent] ); }
}
// FROM HERE ON OUT DONT USE PRIVATE VARIABLES as per directions
polynomial polynomial::derivative() const{
polynomial d;
for (int j = 0; j <= degree(); j++){
d.assign_coef( coefficient(j+1)*(j+1), j );
}
return ( d );
}
double polynomial::eval(double x) const{
double result = coefficient(0); // i changed this to use the function rather than accessing the private array directly
for (int i=1; i<=degree(); i++){
result += coefficient(i) * pow( x, i);
}
return( result );
}
unsigned int polynomial::next_term(unsigned int e) const{
for (int i = (e+1); i <= MAX_EX; i++){
if (coefficient(i) != 0)
return i;
}
return 0;
}
unsigned int polynomial::previous_term(unsigned int e) const{
int prev = UINT_MAX;
for (int i = 0; i < e; i++){
if (coefficient(i) != 0)
prev = i;
}
return prev;
}
//constant operator is inline so nothing to do here
//nonmember binary operators
polynomial operator +(const polynomial& p1, const polynomial& p2){
//double sum;
polynomial polySum;
for (int i = 0; i <= MAX_EX; i++) {
/*sum = (p1.coefficient(i) + p2.coefficient(i));
polySum.assign_coef*/
polySum.add_to_coef(p1.coefficient(i), i);
polySum.add_to_coef(p2.coefficient(i), i);
}
return polySum;
}
//this operator below is done
polynomial operator -(const polynomial& p1, const polynomial& p2){
polynomial polySum;
for (int i = 0; i <= MAX_EX; i++) {
/*sum = (p1.coefficient(i) + p2.coefficient(i));
polySum.assign_coef*/
polySum.add_to_coef(p1.coefficient(i), i);
polySum.add_to_coef((p2.coefficient(i) * -1), i);
}
return polySum;
}
polynomial operator *(const polynomial& p1, const polynomial& p2){
polynomial product;
for (int i = 0; i <= p1.degree(); i++) {
if (p1.coefficient(i) != 0) {
for (int j = 0; j <= p2.degree(); j++) {
if (p2.coefficient(j) != 0)
product.add_to_coef((p1.coefficient(i) * p2.coefficient(j)), (i+j));
}
}
}
return product;
}
//nonmember output function
std::ostream& operator << (std::ostream& out, const polynomial& p){
for (int i = p.degree(); i >= 0; i--) {
// this part is just dealing with the coefficients
if (i == p.degree())
out << p.coefficient( p.degree() );
if (p.coefficient(i) < 0 && i != p.degree())
out << p.coefficient(i) * -1;
if (p.coefficient(i) > 0 && i != p.degree())
out << p.coefficient(i);
// below is dealing with the x and stuff
if (p.coefficient(i) != 0 && i == 1)
out << "x";
if (p.coefficient(i) != 0 && i > 1)
out << "x^" << i;
// below deals with + or -
if (p.previous_term(i) != UINT_MAX) {
if (p.coefficient(p.previous_term(i)) < 0 && p.coefficient(i-1) != 0)
out << " - ";
if (p.coefficient(p.previous_term(i)) > 0 && p.coefficient(i-1) != 0)
out << " + ";
}
}
out << "\n";
return out;
}
}