Question

Can anyone add the 1) add_to_coef, add, multiply, coefficient, eval and equals method in the main function..so can take it from text file.... or 2) make main function with user input for all methods mentioned in the program.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;

public class Polynomial {
//array of doubles to store the coefficients so that the coefficient for x^k is stored in the location [k] of the array.
double coefficients[];
static int size;
//fube the following methods:
public Polynomial() {
//STCONDITION: Creates a polynomial represents 0
coefficients=new double[size+1];
for(int i=0;i<=size;i++)
{
coefficients[i]=0.0;
}
}
public Polynomial(double a0){
//STCONDITION: Creates a polynomial has a single x^0 term with coefficient a0
coefficients=new double[size+1];
for(int i=0;i<=size;i++)
{
coefficients[i]=0.0;
}
coefficients[0]=a0;
}
public Polynomial(Polynomial p){
//STCONDITION: Creates a polynomial is the copy of p
coefficients=new double[Polynomial.size+1];
for(int i=0;i<=size;i++)
{
coefficients[i]=p.coefficient(i);
}
}
public void add_to_coef(double amount, int exponent){
// STCONDITION: Adds the given amount to the coefficient of the specified exponent.
if(exponent<=size)
coefficients[exponent]=coefficients[exponent]+amount;
}
public void assign_coef(double coefficient, int exponent){
//STCONDITION: Sets the coefficient for the specified exponent.
coefficients[exponent]=coefficient;
}
public double coefficient(int exponent)
{
//STCONDITION: Returns coefficient at specified exponent of this polynomial.
return coefficients[exponent];
}
public double eval(double x)
{
//STCONDITION: The return value is the value of this polynomial with the given value for the variable x.
double result=0;
for(int i=0;i<=size;i++)
{
result+=coefficients[i]* Math.pow(x, i);
}
return result;
}
public boolean equals (Polynomial p)
{
//STCONDITION: return true if p and this polynomial is same
for(int i=0;i<=size;i++)
{
if(coefficients[i]!=p.coefficient(i))
return false;
}
return true;
}
  
public String toString()
{
//STCONDITION: return the polynomial as a string like "2x^2 + 3x + 4"
//portant only non-zero terms
String result="";
for(int i=size;i>=0;i--)
{
if(coefficients[i]!=0.0)
{
if(i==0)
result+=coefficients[i];
else if(i==1)
result+=coefficients[i]+"x +";
else
result+=coefficients[i]+"x^"+String.valueOf(i)+" + ";
}
}
return result;
}
  
public Polynomial add(Polynomial p)
{
//STCONDITION: return a polynomial that is the sum of p and this polynomial
Polynomial result=new Polynomial();
for(int i=0;i<=size;i++)
{
result.add_to_coef(coefficients[i]+p.coefficient(i), i);
}
return result;
}
public Polynomial multiply(Polynomial p)
{
//STCONDITION: returns a new polynomial obtained by multiplying this term and p. For example, if this polynomial is
//^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.
Polynomial result=new Polynomial();
for (int i=0; i<=size; i++)
{
for (int j=0; j<=size; j++)
{
result.add_to_coef((coefficients[i]*p.coefficient(j)),(i+j));
}
}
return result;
}
  
public static void main(String args[]) throws FileNotFoundException, IOException
{
double coef;
int expo;
//Scanner in = new Scanner(new File("input.txt"));
Scanner in = new Scanner(new File("F:\\Netbeans Files\\Application7\\src\\polynomial\\polynomialA.txt"));
Polynomial.size=Integer.parseInt(in.nextLine());

//create object for polynomial class
Polynomial polynomialA=new Polynomial();

while (in.hasNext()) {
String ss=in.nextLine();
coef = Double.parseDouble(ss.substring(ss.indexOf("(") + 1, ss.indexOf(",")));
expo=Integer.parseInt(ss.substring(ss.indexOf(",") + 1, ss.indexOf(")")));
polynomialA.assign_coef(coef, expo);
}
if (in != null) {
in.close();
}
System.out.println(polynomialA);
}
}

Answer 1

Solution==========================

Note: The question appears to be ambigous,

• Please provide, how the input file actually looks like in the comments section..
• If there are no rules of how input file looks like, let me know that too..

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;

public class Polynomial {
   // array of doubles to store the coefficients so that the coefficient for
   // x^k is stored in the location [k] of the array.
   double coefficients[];
   static int size;

   // fube the following methods:
   public Polynomial() {
       // STCONDITION: Creates a polynomial represents 0
       coefficients = new double[size + 1];
       for (int i = 0; i <= size; i++) {
           coefficients[i] = 0.0;
       }
   }

   public Polynomial(double a0) {
       // STCONDITION: Creates a polynomial has a single x^0 term with
       // coefficient a0
       coefficients = new double[size + 1];
       for (int i = 0; i <= size; i++) {
           coefficients[i] = 0.0;
       }
       coefficients[0] = a0;
   }

   public Polynomial(Polynomial p) {
       // STCONDITION: Creates a polynomial is the copy of p
       coefficients = new double[Polynomial.size + 1];
       for (int i = 0; i <= size; i++) {
           coefficients[i] = p.coefficient(i);
       }
   }

   public void add_to_coef(double amount, int exponent) {
       // STCONDITION: Adds the given amount to the coefficient of the
       // specified exponent.
       if (exponent <= size)
           coefficients[exponent] = coefficients[exponent] + amount;
   }

   public void assign_coef(double coefficient, int exponent) {
       // STCONDITION: Sets the coefficient for the specified exponent.
       coefficients[exponent] = coefficient;
   }

   public double coefficient(int exponent) {
       // STCONDITION: Returns coefficient at specified exponent of this
       // polynomial.
       return coefficients[exponent];
   }

   public double eval(double x) {
       // STCONDITION: The return value is the value of this polynomial with
       // the given value for the variable x.
       double result = 0;
       for (int i = 0; i <= size; i++) {
           result += coefficients[i] * Math.pow(x, i);
       }
       return result;
   }

   public boolean equals(Polynomial p) {
       // STCONDITION: return true if p and this polynomial is same
       for (int i = 0; i <= size; i++) {
           if (coefficients[i] != p.coefficient(i))
               return false;
       }
       return true;
   }

   public String toString() {
       // STCONDITION: return the polynomial as a string like "2x^2 + 3x + 4"
       // portant only non-zero terms
       String result = "";
       for (int i = size; i >= 0; i--) {
           if (coefficients[i] != 0.0) {
               if (i == 0)
                   result += coefficients[i];
               else if (i == 1)
                   result += coefficients[i] + "x +";
               else
                   result += coefficients[i] + "x^" + String.valueOf(i) + " + ";
           }
       }
       return result;
   }

   public Polynomial add(Polynomial p) {
       // STCONDITION: return a polynomial that is the sum of p and this
       // polynomial
       Polynomial result = new Polynomial();
       for (int i = 0; i <= size; i++) {
           result.add_to_coef(coefficients[i] + p.coefficient(i), i);
       }
       return result;
   }

   public Polynomial multiply(Polynomial p) {
       // STCONDITION: returns a new polynomial obtained by multiplying this
       // term and p. For example, if this polynomial is
       // ^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.
       Polynomial result = new Polynomial();
       for (int i = 0; i <= size; i++) {
           for (int j = 0; j <= size; j++) {
               result.add_to_coef((coefficients[i] * p.coefficient(j)), (i + j));
           }
       }
       return result;
   }

   public static void main(String args[]) throws FileNotFoundException, IOException {
       double coef;
       int expo;
       Scanner in = new Scanner(new File("input.txt"));
       //Scanner in = new Scanner(new File("F:\\Netbeans Files\\Application7\\src\\polynomial\\polynomialA.txt"));
      
       Polynomial.size = Integer.parseInt(in.nextLine());

       // create object for polynomial class
       Polynomial polynomialA = new Polynomial();
      
       while (in.hasNext()) {
           String ss = in.nextLine();

//Added trim method, to eleminate any errouneous whitespaces
coef = Double.parseDouble(ss.substring(ss.indexOf("(") + 1, ss.indexOf(",")).trim());
           expo = Integer.parseInt(ss.substring(ss.indexOf(",") + 1, ss.indexOf(")")).trim());
           polynomialA.assign_coef(coef, expo);
       }
       if (in != null) {
           in.close();
       }
      
      
       System.out.println(polynomialA);
       System.out.println("For x = 5");
       System.out.println(polynomialA.eval(5));
      
   }
}

================

For input file which looks like this (as provided in comments)

D Polynomial javaoinput.brt Polynomial.java 1 100 2 (3,0) 3 (-1,3) 4 (4,100) polynomialA.txt

The output looks as:

4.0x*100+ -1.0x*3 + 3.0 For x- 5 3.155443620884047E70