Answer to Question #251046 in C++ for SCADA HDMI

Question

Use the array ADT to compute the addition and subtraction of two polynomials.

The interface of your program must look like this one:

Enter the degree of polynomial for p(x) : 5

Enter the coefficient of x^0 : 0

Enter the coefficient of x^1 : 4

Enter the coefficient of x^2 : 5

Enter the coefficient of x^3 : 0

Enter the coefficient of x^4 : 6

Enter the coefficient of x^5 : 4

Enter the degree of polynomial for q(x) : 3

Enter the coefficient of x^0 : 3

Enter the coefficient of x^1 : -2

Enter the coefficient of x^2 : 3

Enter the coefficient of x^3 : 10

First Polynomial p(x) = 4x^5 + 6x^4 + 5x^2 + 4x

Second Polynomial q(x) = 10x^3 + 3x^2 – 2x + 3

p(x) + q(x) = 4x^5 + 6x^4 +10x^3 + 8x^2 + 2x + 3

p(x) – q(x) = 4x^5 + 6x^4 – 10x^3 + 2x^2 + 6x – 3

The numbers in Red are entered by the user.

Hint:

Use 1D array to store the polynomials:

For the above example, the polynomials will be stored like this:

Index 0 1 2 3 4 5

p(x) Coefficient 0 4 5 0 6 4

Index 0 1 2 3

q(x) Coefficient 3 -2 3 10

Answer 1

#include <iostream>
#include <math.h>
using namespace std;
class Polynomial{
    int *coefs, deg;
    public:
    Polynomial(){
        coefs = NULL;
    }
    Polynomial(int degree){
        this->deg = degree;
        coefs = (int*) malloc(sizeof(int) * (degree + 1));
        for(int i = 0; i <= degree; i++){
            cout<<"Enter the coefficient of x^"<<i<<":";
            cin>>coefs[i];
        }
    }
    Polynomial operator+(const Polynomial &other){
        Polynomial result;
        if(this->deg > other.deg){
            result.deg = this->deg;
            result.coefs = (int *) malloc(sizeof(int) * (result.deg + 1));
            int i = 0;
            for(i = 0; i <= other.deg; i++){
                result.coefs[i] = this->coefs[i] + other.coefs[i];
            }
            for(i; i <= result.deg; i++){
                result.coefs[i] = this->coefs[i];
            }
        }
        else{
            result.deg = other.deg;
            result.coefs = (int *) malloc(sizeof(int) * (result.deg + 1));
            int i = 0;
            for(i = 0; i <= this->deg; i++){
                result.coefs[i] = this->coefs[i] + other.coefs[i];
            }
            for(i; i <= result.deg; i++){
                result.coefs[i] = other.coefs[i];
            }
        }
        return result;
    }
    Polynomial operator-(const Polynomial &other){
        Polynomial temp;
        temp.deg = other.deg;
        temp.coefs = (int*) malloc(sizeof(int) * (other.deg + 1));
        for(int i = 0; i <= other.deg; i++){
            temp.coefs[i] = -1 * other.coefs[i];
        }
        return *this + temp;
    }
    void print(){
        for(int i = this->deg; i >= 0; i--){
            if(coefs[i] != 0){
                if(coefs[i] < 0) cout<<" - ";
                else if(i != this->deg) cout<<" + ";
                cout<<abs(coefs[i]);
                if(i == 1) cout<<"x";
                else if(i != 0) cout<<"x^"<<i;
            }
        }
    }
    ~Polynomial(){
        if(coefs != NULL) delete this->coefs;
    }
};


int main(){
    int dp, dq;
    cout<<"Enter the degree of polynomial for p(x):";
    cin>>dp;
    Polynomial p(dp);
    cout<<"Enter the degree of polynomial for q(x):";
    cin>>dq;
    Polynomial q(dq);
    cout<<"First Polynomial p(x) = "; p.print();
    cout<<"\nSecond Polynomial q(x) = "; q.print();


    cout<<"\np(x) + q(x) = "; (p + q).print();
    cout<<"\np(x) - q(x) = "; (p - q).print();
    return 0;
}