Homework: Polynomial Using Array Description: Implement a polynomial class (1) N
ID: 3888919 • Letter: H
Question
Homework: Polynomial Using Array Description: Implement a polynomial class (1) Name your class Polynomial (2) Use array of doubles to store the coefficients so that the coefficient for x^k is stored in the location [k] of the array. (3) define the following methods: a. public Polynomial() POSTCONDITION: Creates a polynomial represents 0 b. public Polynomial(double a0) POSTCONDITION: Creates a polynomial has a single x^0 term with coefficient a0 c. public Polynomial(Polynomial p) POSTCONDITION: Creates a polynomial is the copy of p d. public void add_to_coef(double amount, int exponent) POSTCONDITION: Adds the given amount to the coefficient of the specified exponent. Note: the exponent is allowed to be greater than the degree of the polynomial example: if p = x + 1, after p.add_to_coef(1, 2), p = x^2 + x + 1 e. public void assign_coef(double coefficient, int exponent) POSTCONDITION: Sets the coefficient for the specified exponent. Note: the exponent is allowed to be greater than the degree of the polynomial f. public double coefficient(int exponent) POSTCONDITION: Returns coefficient at specified exponent of this polynomial. Note: the exponent is allowed to be greater than the degree of the polynomial e.g. if p = x + 1; p.coeffcient(3) should return 0 g. public double eval(double x) POSTCONDITION: The return value is the value of this polynomial with the given value for the variable x. Do not use power method from Math, which is very low efficient h. public boolean equals (Object p) POSTCONDITION: return true if p is a polynomial and it has same terms as this polynomial i. public string toString() POSTCONDITION: return the polynomial as a string like “2x^2 + 3x + 4” Important only non-zero terms j. public Polynomial add(Polynomial p) POSTCONDITION: this object and p are not changed return a polynomial that is the sum of p and this polynomial k. public Polynomial multiply(Polynomial p) POSTCONDITION: this object and p should not be changed returns a new polynomial obtained by multiplying this term and p. For example, if this polynomial is 2x^2 + 3x + 4 and p is 5x^2 - 1x + 7, then at the end of this function, it will return the polynomial 10x^4 + 13x^3 + 31x^2 + 17x + 28. l. Write a single main method to test ALL the methods and classes. You can read from the keyboard, or from the file. The format of the file should be: first line specifies the maximum degree, then followed by the terms, one per line. You can assume they are in the right order. For example: polynomialA.txt 100 (3,0) (-1, 3)
Explanation / Answer
import java.lang.Math; // headers MUST be above the first class
public class Polynomial
{
int degree=0;
double[] coeff;
public Polynomial(){
degree=0;
coeff = new double[1];
coeff[0]=0;
}
public Polynomial(double a0){
degree=0;
coeff = new double[1];
coeff[0]=a0;
}
public Polynomial(Polynomial p){
degree=p.degree;
coeff = new double[degree+1];
for(int i=0;i<=degree;i++){
coeff[i]=p.coeff[i];
}
}
public void add_to_coef(double amount, int exponent){
if(exponent>degree){
double[] coeff1=new double[exponent];
for(int i=0;i<=degree;i++){
coeff1[i]=coeff[i];
}
coeff=coeff1;
}
coeff[exponent]=coeff[exponent]+amount;
}
public void assign_coef(double coefficient, int exponent){
if(exponent>degree){
double[] coeff1=new double[exponent];
for(int i=0;i<=degree;i++){
coeff1[i]=coeff[i];
}
coeff=coeff1;
}
coeff[exponent]=coefficient;
}
public double coefficient(int exponent) {
if(exponent>degree) return 0;
else return coeff[exponent];
}
public double eval(double x){
double value=0;
for(int i=0;i<=degree;i++){
double prod=1;
for(int j=0;j<i;j++){
prod=prod*x;
}
value = value + coeff[i]*prod;
}
return value;
}
public boolean equals (Object p){
if(!(p instanceof Polynomial)) return false;
Polynomial p1=(Polynomial)p;
if(!(p1.degree==degree)) return false;
for(int i=0;i<degree;i++){
if(!(coeff[i]==p1.coeff[i]))return false;
}
return true;
}
public String toString(){
String str="";
for(int i=degree;i>=0;i--){
if(coeff[i]!=0){
if(i>0){
str=str+coeff[i]+"x^"+i;
str=str+"+";
}
else{
str=str+coeff[0];
}
}
}
return str;
}
public Polynomial add(Polynomial p){
Polynomial np;
if(degree>p.degree){
np=new Polynomial(this);
for(int i=0;i<=p.degree;i++){
np.coeff[i]=np.coeff[i]+p.coeff[i];
}
return np;
}
else{
np=new Polynomial(p);
for(int i=0;i<=degree;i++){
np.coeff[i]=np.coeff[i]+coeff[i];
}
return np;
}
}
public static void main(String[] args)
{
Polynomial p = new Polynomial();
p=new Polynomial(2);
Polynomial p1=new Polynomial(p);
p1=p1.add(p);
System.out.println("-----");
System.out.println(p1.toString());
}
}
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