polynomial division c++ code example

Example: divide two polynomials c++

#include <iostream>#include <iterator>#include <vector> using namespace std;typedef vector<double> Poly; // does:  prints all members of vector// input: c - ASCII char with the name of the vector//        A - reference to polynomial (vector)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;        // vectors - N / D == q && N % D == r	size_t dN, dD, dd, dq, dr; // degrees of vectors	size_t i;                  // loop counter 	// setting the degrees of vectors	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;	} 	// allocation and initialization of vectors	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 equals D shifted right			d.assign(d.size(), 0); 			for( i = 0 ; i <= dD ; i++ )				d[i+dN-dD] = D[i];			dd = dN; 			Print( 'd', d ); 			// calculating one element of q			q[dN-dD] = N[dN]/d[dd]; 			Print( 'q', q ); 			// d equals d * q[dN-dD]			for( i = 0 ; i < dq + 1 ; i++ )				d[i] = d[i] * q[dN-dD]; 			Print( 'd', d ); 			// N equals N - d			for( i = 0 ; i < dN + 1 ; i++ )				N[i] = N[i] - d[i];			dN--; 			Print( 'N', N );			cout << "-----------------------" << endl << endl; 		}	} 	// r equals N 	for( i = 0 ; i <= dN ; i++ )		r[i] = N[i]; 	cout << "=========================" << endl << endl;	cout << "-- Result --" << endl << endl; 	Print( 'q', q );	Print( 'r', r );}