PA1 - úkol 5.2 (Násobení polynomů)

#include <iostream>
using namespace std;
#define err "Nespravny vstup." << endl

int main ( int argc, char * argv[] )
 {
    // read and check polynomial A
    int n;
    cout << "Zadejte stupen polynomu A:" << endl;
    cin >> n;
    if ( cin.fail() || n < 0 )
     {
        cout << err;
        return 1;
     }

    int * pA = new int[n+1];
    cout << "Zadejte koeficienty polynomu A:" << endl;
    for (int i = n ; i >= 0; i--)
     {
        cin >> pA[i];
        if ( cin.fail() )
         {
            cout << err;
            delete[] pA;
            return 1;
         }
     }

    // read and check polynomial B
    int m;
    cout << "Zadejte stupen polynomu B:" << endl;
    cin >> m;
    if ( cin.fail() || m < 0)
     {
        cout << err;
        delete[] pA;
        return 1;
     }

    int * pB = new int[m+1];
    cout << "Zadejte koeficienty polynomu B:" << endl;
    for ( int i = m ; i >= 0; i--)
     {
        cin >> pB[i];
        if ( cin.fail() )
         {
            cout << err;
            delete[] pA;
            delete[] pB;
            return 1;
         }
     }

    //declare and initialize array for result
    int * res = new int[m+n+1];
    for ( int i = m+n; i >= 0 ; i-- )
        res[i] = 0;

    // count each witch each coz im not brave enought to implement FFT :-)
    for ( int i = n; i >= 0; i-- )
     {
        for ( int j = m; j >= 0; j-- )
         {
            res[i+j] += pA[i] * pB[j];
         }
     }

    //print result
    bool first = true;
    bool zero = true;
    for ( int i = m+n; i >= 0 ; i-- )
     {
        if ( res[i] == 0 ) //suppress print of elements with zero coefficient
            continue;
        if ( first ) //print first element
         {
            if ( res[i] > 1 || res[i] < -1 )
             {
                cout << res[i];
                zero = false;
             }
            else if ( res[i] == -1 )
             {
                cout << "-";
                zero = false;
             }
            first = false;
         }
        else //print other elements
         {
            if ( res[i] > 1 || res[i] < -1  ||  i == 0  )
             {
                cout << showpos << res[i];
                zero = false;
             }
            else if ( res[i] == 1 )
                    cout << "+";
                 else
                    cout << "-";
         }
        if ( i != 0 ) // suppress print of x with zero exponent
         {
            cout << "x";
            zero = false;
         }

        if ( i != 1 && i != 0 ) // print only non-one and non-zero exponents
            cout << "<sup>" << noshowpos << i << "</sup>";
     }
    if ( zero )
        cout << "0";
    cout << endl;

    //free memory and terminate
    delete[] pA;
    delete[] pB;
    delete[] res;
    return 0;
 }