Question

所以在我的主要部分，我有两个多项式A和B，我试图添加多项式，输出新的多项式，然后从A中减去多项式B然后输出。但问题是在加法函数之后，当我调用减法函数时，它在求和的多项式上执行减法而不是新的多项式A和B.

主要

中的电话

outfile << "Printing addition of the first polynomial and the second polynomial" << endl << endl;
linkedList polynomialD;
polynomialD = polynomialD.polynomialAddition(polynomialA, polynomialB);
polynomialD.printList(outfile);

outfile << endl;
outfile << "Printing subtraction of the second polynomial from the first polynomial" << endl << endl;
linkedList polynomialE;
polynomialE = polynomialE.polynomialSubtraction(polynomialA, polynomialB);
polynomialE.printList(outfile);

这是我的程序输出的内容：

Polynomial in canonical form - 
(6x^6) + (9x^2) + (-5)

Polynomial in canonical form - 
(7x^7) + (2x^5) + (7x^2) + (12)

Printing addition of the first polynomial and the second polynomial

Polynomial in canonical form - 
(7x^7) + (6x^6) + (2x^5) + (16x^2) + (7)


Printing subtraction of the second polynomial from the first polynomial

Polynomial in canonical form - 
(0x^7) + (6x^6) + (0x^5) + (9x^2) + (-5)

但它应该打印出来：

Polynomial in canonical form - 
(6x^6) + (9x^2) + (-5)

Polynomial in canonical form - 
(7x^7) + (2x^5) + (7x^2) + (12)

Printing addition of the first polynomial and the second polynomial

Polynomial in canonical form - 
(7x^7) + (6x^6) + (2x^5) + (16x^2) + (7)


Printing subtraction of the second polynomial from the first polynomial

Polynomial in canonical form - 
(-7x^7) + (6x^6) + (-2x^5) + (2x^2) + (-17)

由于某种原因，加法函数使其表现得像它存在，所以当它试图进行减法时，它会发现当前存在的节点，它不应该存在。

//Function to insert into the linked list
void listInsert(int coefficient, int exponent)
{
    Node *spot = findSpot (coefficient, exponent);

    if(spot->exponent == exponent )
    {
        int temp;
        temp = spot->coefficient + coefficient;
        spot->coefficient = temp;
    }
    else
    {
        Node* newNode = new Node(coefficient, exponent);
        newNode->next = spot->next;
        spot->next = newNode;
    }
}

//Function used to insert into the linked list but subtracting like powers.
void listInsertSubtraction(int coefficient, int exponent)
{
    Node *spot = findSpot (coefficient, exponent);

    if(spot->exponent == exponent )
    {
        int temp;
        temp = spot->coefficient - coefficient;
        spot->coefficient = temp;        
    }
    else
    {
        int tempcoeff;
        tempcoeff = -coefficient;

        Node* newNode = new Node(coefficient, exponent);
        newNode->next = spot->next;
        spot->next = newNode;
    }
}

//Function to add two polynomials.
linkedList polynomialAddition (linkedList& polynomialA, linkedList& polynomialB)
{
    linkedList newPolynomial = polynomialA;

    //Temporary Nodes point to the first element of each linked list.
    Node* tempNodeB = polynomialB.listHead->next;

    while (tempNodeB != NULL)
    {
        newPolynomial.listInsert (tempNodeB->coefficient, tempNodeB->exponent);
        tempNodeB = tempNodeB->next;
    }
    return newPolynomial;
}

//Function to subtract the 2nd polynomial from the first polynomial.
linkedList polynomialSubtraction (linkedList& polynomialA, linkedList& polynomialB)
{
    linkedList newPolynomial = polynomialA;

    //Temporary Nodes point to the first element of each linked list.
    Node* tempNodeB = polynomialB.listHead->next;

    while (tempNodeB != NULL)
    {
        newPolynomial.listInsertSubtraction (tempNodeB->coefficient, tempNodeB->exponent);
        tempNodeB = tempNodeB->next; 
    }
    return newPolynomial;
}

我尝试乱搞并更改通过引用传递的参数，作为指针，将返回更改为指针而不是值，但是当我尝试运行它时，它只是说运行失败。

编辑：添加findSpot功能

Node* findSpot (int coefficient, int exponent)
{
    Node *spot = listHead;

    while(spot->next != NULL && spot->next->exponent >= exponent)
    {
        spot = spot->next;
    }

  return spot;  
}

如果需要，还有一个指向整个代码的pastebin链接 - http://pastebin.com/yL85Xif2

Answer 1

当您执行linkedList newPolynomial = polynomialA;时，对我来说，您不是使用polynomialA列表创建新列表。

如果您在添加后打印polynomialA，则会看到它已被修改，这就是为什么在您减去后会得到0x^7之类的内容。为了保留您的算法，您应该复制polynomialA并将其用作newPolynomial。

链接列表加法/减法函数是否正在改变参数的值？

1 个答案: