Task: Polynomial long division


C++: #include <iostream>
#include <iterator>
#include <vector>

using namespace std;
typedef vector<double> Poly;




void Print(char name, const Poly &A) {
	cout << name << "(" << A.size()-1 << ") = [ ";
	copy(A.begin(), A.end(), ostream_iterator<decltype(A[0])>(cout, " "));
	cout << "]\n";
}

int main() {
	Poly N, D, d, q, r;        
	size_t dN, dD, dd, dq, dr; 
	size_t i;                  

	
	cout << "Enter the degree of N: ";
	cin >> dN;
	cout << "Enter the degree of D: "; 
	cin >> dD;
	dq = dN-dD;  
	dr = dN-dD;

	if( dD < 1 || dN < 1 ) {
		cerr << "Error: degree of D and N must be positive.\n";
		return 1;
	}

	
	N.resize(dN+1);
	cout << "Enter the coefficients of N:"<<endl;  
	for ( i = 0; i <= dN; i++ ) {
		cout << "N[" << i << "]= ";
		cin >> N[i];
	}

	D.resize(dN+1);
	cout << "Enter the coefficients of D:"<<endl;	
	for ( i = 0; i <= dD; i++ ) {
		cout << "D[" << i << "]= ";
		cin >> D[i];
	}

	d.resize(dN+1);
	q.resize(dq+1);
	r.resize(dr+1);

	cout << "-- Procedure --" << endl << endl;
	if( dN >= dD ) {
		while(dN >= dD) {
			
			d.assign(d.size(), 0);

			for( i = 0 ; i <= dD ; i++ )
				d[i+dN-dD] = D[i];
			dd = dN;

			Print( 'd', d );

			
			q[dN-dD] = N[dN]/d[dd];

			Print( 'q', q );

			
			for( i = 0 ; i < dq + 1 ; i++ )
				d[i] = d[i] * q[dN-dD];

			Print( 'd', d );

			
			for( i = 0 ; i < dN + 1 ; i++ )
				N[i] = N[i] - d[i];
			dN--;

			Print( 'N', N );
			cout << "-----------------------" << endl << endl;

		}
	}

	
	for( i = 0 ; i <= dN ; i++ )
		r[i] = N[i];

	cout << "=========================" << endl << endl;
	cout << "-- Result --" << endl << endl;

	Print( 'q', q );
	Print( 'r', r );
}


C#: using System;

namespace PolynomialLongDivision {
    class Solution {
        public Solution(double[] q, double[] r) {
            Quotient = q;
            Remainder = r;
        }

        public double[] Quotient { get; }
        public double[] Remainder { get; }
    }

    class Program {
        static int PolyDegree(double[] p) {
            for (int i = p.Length - 1; i >= 0; --i) {
                if (p[i] != 0.0) return i;
            }
            return int.MinValue;
        }

        static double[] PolyShiftRight(double[] p, int places) {
            if (places <= 0) return p;
            int pd = PolyDegree(p);
            if (pd + places >= p.Length) {
                throw new ArgumentOutOfRangeException("The number of places to be shifted is too large");
            }
            double[] d = new double[p.Length];
            p.CopyTo(d, 0);
            for (int i = pd; i >= 0; --i) {
                d[i + places] = d[i];
                d[i] = 0.0;
            }
            return d;
        }

        static void PolyMultiply(double[] p, double m) {
            for (int i = 0; i < p.Length; ++i) {
                p[i] *= m;
            }
        }

        static void PolySubtract(double[] p, double[] s) {
            for (int i = 0; i < p.Length; ++i) {
                p[i] -= s[i];
            }
        }

        static Solution PolyLongDiv(double[] n, double[] d) {
            if (n.Length != d.Length) {
                throw new ArgumentException("Numerator and denominator vectors must have the same size");
            }
            int nd = PolyDegree(n);
            int dd = PolyDegree(d);
            if (dd < 0) {
                throw new ArgumentException("Divisor must have at least one one-zero coefficient");
            }
            if (nd < dd) {
                throw new ArgumentException("The degree of the divisor cannot exceed that of the numerator");
            }
            double[] n2 = new double[n.Length];
            n.CopyTo(n2, 0);
            double[] q = new double[n.Length];
            while (nd >= dd) {
                double[] d2 = PolyShiftRight(d, nd - dd);
                q[nd - dd] = n2[nd] / d2[nd];
                PolyMultiply(d2, q[nd - dd]);
                PolySubtract(n2, d2);
                nd = PolyDegree(n2);
            }
            return new Solution(q, n2);
        }

        static void PolyShow(double[] p) {
            int pd = PolyDegree(p);
            for (int i = pd; i >= 0; --i) {
                double coeff = p[i];
                if (coeff == 0.0) continue;
                if (coeff == 1.0) {
                    if (i < pd) {
                        Console.Write(" + ");
                    }
                } else if (coeff == -1.0) {
                    if (i < pd) {
                        Console.Write(" - ");
                    } else {
                        Console.Write("-");
                    }
                } else if (coeff < 0.0) {
                    if (i < pd) {
                        Console.Write(" - {0:F1}", -coeff);
                    } else {
                        Console.Write("{0:F1}", coeff);
                    }
                } else {
                    if (i < pd) {
                        Console.Write(" + {0:F1}", coeff);
                    } else {
                        Console.Write("{0:F1}", coeff);
                    }
                }
                if (i > 1) Console.Write("x^{0}", i);
                else if (i == 1) Console.Write("x");
            }
            Console.WriteLine();
        }

        static void Main(string[] args) {
            double[] n = { -42.0, 0.0, -12.0, 1.0 };
            double[] d = { -3.0, 1.0, 0.0, 0.0 };
            Console.Write("Numerator   : ");
            PolyShow(n);
            Console.Write("Denominator : ");
            PolyShow(d);
            Console.WriteLine("-------------------------------------");
            Solution sol = PolyLongDiv(n, d);
            Console.Write("Quotient    : ");
            PolyShow(sol.Quotient);
            Console.Write("Remainder   : ");
            PolyShow(sol.Remainder);
        }
    }
}