计算两个多项式的gcd时无效的分配大小

Question

我试图使用以下代码计算2个多项式的最大公约数：

void Print(char c, int d, double* A) {
     int i;
     for (i = 0; i < d + 1; i++)
            cout << c << "[" << i << "]= " << A[i] << endl;
    cout << "Degree of " << c << ": " << d << endl << endl;
}
double* dividePolynomials(double* pol, double* div,int n,int m,int& count){
    double *N,*D,*d, *q, *r;
    int dN, dD, dd, dq, dr;
    int i;
    dN = n;
    dD = m;
    dq = dN - dD;
    dr = dN - dD;
    N = new double[n + 1];
    D = new double[n + 1];
    for (int i = 0; i <= n; i++)
        N[i] = pol[i];
    for (int i = 0; i <= dD; i++)
        D[i] = div[i];
    d = new double[dN + 1];
    for (i = dD + 1; i < dN + 1; i++) {
        D[i] = 0;
    }
    q = new double[dq + 1];
    for (i = 0; i < dq + 1; i++) {
        q[i] = 0;
    }

    r = new double[dr + 1];
    for (i = 0; i < dr + 1; i++) {
        r[i] = 0;
    }

    if (dD < 0) {
        cout << "Degree of D is less than zero. Error!";
    }

    cout << "-- Procedure --" << endl << endl;
    if (dN >= dD) {
        while (dN >= dD) {
            // d equals D shifted right
            for (i = 0; i < dN + 1; i++) {
                d[i] = 0;
            }
            for (i = 0; i < dD + 1; i++) {
                d[i + dN - dD] = D[i];
            }
            dd = dN;
            Print('d', dd, d);
            // calculating one element of q
            q[dN - dD] = N[dN] / d[dd];
            Print('q', dq, q);
            // d equals d * q[dN-dD]
            for (i = 0; i < dd + 1; i++) {
                d[i] = d[i] * q[dN - dD];
            }
            Print('d', dd, d);
            // N equals N - d
            for (i = 0; i < dN + 1; i++) {
                N[i] = N[i] - d[i];
            }
            dN--;
            Print('N', dN, N);
            cout << "-----------------------" << endl << endl;

        }

    }

    // r equals N
    for (i = 0; i < dN + 1; i++) {
        r[i] = N[i];
    }
    dr = dN;
    cout << "=========================" << endl << endl;
    cout << "-- Result --" << endl << endl;

    Print('q', dq, q);
    Print('r', dr, r);
    count = dr;
    /*delete[] N;
    delete[] D;
    delete[] d;
    delete[] r;*/
    return r;
}
double* euclid_gcd_recur(double* m, double* n, int dega, int degb)
{
    int deg;
    double* temp;
    temp=dividePolynomials(m, n, dega, degb, deg);
    if (n == 0)
        return m;
    return euclid_gcd_recur(n,temp,degb,deg);
}
int main() {
    int n, a;
    cout << "Enter the degree of the first polynomial" << endl;
    cin >> n;
    double* poly = new double[n+1];
    cout << "Enter the coefficients of polynomial N:" << endl;
    for (int i = 0; i < n + 1; i++) {
        cout << "N[" << i << "]= " << endl;
        cin >> poly[i];
    };
    cout << "Enter the degree of the second polynomial" << endl;
    cin >> a;
    double* poly1 = new double[a + 1];
    cout << "Enter the coefficients of polynomial M:" << endl;
    for (int i = 0; i < a + 1; i++) {
        cout << "M[" << i << "]= " << endl;
        cin >> poly1[i];
    };
    double* t;
    t=euclid_gcd_recur(poly, poly1, n, a);
    system("pause");
    return 0;
}

当我尝试编译此程序时，出现以下错误：

Answer 1

你有：

D = new double[n + 1];

for (int i = 0; i <= dD; i++)
    D[i] = div[i];

不清楚n和dD之间的关系是什么。

您需要将第一行更改为：

D = new double[dD + 1];    // Use dD, not n

或将循环更改为：

for (int i = 0; i <= n; i++)  // Use n, not dD.
    D[i] = div[i];

我不清楚哪一个应该改变。