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POpolynomial linked list with two structs and its problems
 

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  1. POpolynomial linked list with two structs and its problems
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    <pre><code>#include &lt;iostream&gt; using namespace std; struct Term; struct Node; typedef Term* termPtr; typedef Node* list; list cons(int degree,int coeff, list p); struct Term { int degree; int coeff; }; struct Node { termPtr term; list link; }; class polynomial { private: list poly; static const int VARIABLE_X='X'; char variable; public: polynomial():poly(NULL),variable(VARIABLE_X){}; polynomial(int coef,int deg); polynomial insert (termPtr t,list p); int degree() const; int coeff(int n) const; void setPrintVariable (char x){variable=x;} char getPrintVariable()const { return variable;} friend const polynomial readPoly(); friend void printPoly(polynomial a); void deletePoly(); friend const polynomial operator +(const polynomial &amp;a,const polynomial &amp;b); friend const polynomial operator *(const polynomial &amp;a,const polynomial &amp;b); }; polynomial::polynomial(int c,int d) { if(poly == NULL)//compiler doesnt understand this part poly = cons(c,d,poly); else // i put my cons here just to make the poly poly=cons(c,d,poly); } list cons(int c,int d, list p) { termPtr aterm = new Term; aterm-&gt;coeff=c; aterm-&gt;degree=d; list q = new Node; q-&gt;term = aterm; q-&gt;link = p; return q; } void printPoly (polynomial a) { cout&lt;&lt;"["; if(a.poly == NULL) cout&lt;&lt;"]"; else while(a.poly != NULL) { cout&lt;&lt;"("&lt;&lt;a.poly-&gt;term-&gt;coeff&lt;&lt;" X "&lt;&lt;a.poly-&gt;term-&gt;degree; a.poly=a.poly-&gt;link ; } cout&lt;&lt;endl; } </code></pre> <p>This code is using linked lists to store polynomials. One struct is for the polynomial degree and coeff; another struct is for making a Node in order to create a linked list.</p> <p>I have two problems with the code:</p> <ol> <li><p>An empty polynomial which is NULL but in the constructor my condition statement doesn't find it out.</p></li> <li><p>Why my print method doesn't work.</p></li> </ol> <p>I have this problem in the print method</p> <blockquote> <p>Unhandled exception at 0x00c1166b in polynomial.exe: 0xC0000005: Access violation reading location 0xcccccccc.</p> </blockquote>
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    1. PO
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    1. This table or related slice is empty.
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    1. USJonathan Leffler
    1. USfemchi
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. CO1. What do you mean by "compiler doesn't understand that poly is NULL"? What is the compiler doing and why do you believe it to be wrong? 2. In what way does your print method not work? What does it do? What did you hope it would do instead?
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      1. POpolynomial linked list with two structs and its problems
      1. USGareth McCaughan
    2. COwhile I debug it, the condition in the construction ( if (poly==NULL)) is ignored
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      1. POpolynomial linked list with two structs and its problems
      1. USfemchi
    3. CO1. What do you mean by "is ignored"? How do you know it's being ignored? 2. Speaking of ignoring things, you ignored my second question.
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      1. POpolynomial linked list with two structs and its problems
      1. USGareth McCaughan
 

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