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POc++ use of *& as parameter (Pointer fun, tertiary tree method)
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copied!<p>I'm trying to write a method which adds a key-value pair to a tertiary tree, but I'm obviously doing something wrong as I get a segfault whenever I reach the marked code</p> <pre><code>void Tree::add(int k, Node *&r) { cout<<"add"<<endl; if(r==NULL){ r = new Node(k); //check(heap area); } </code></pre> <p><strong>begin problem code</strong></p> <pre><code> else if(r->keyCount == 1){ cout<<"adding second key"; if(r->getKey() < k){ Node * temp = new Node(r->getKey(),k,r->data[0],0); delete r; r = temp; r->keyCount++; cout<<"test"<<endl; } else { Node * temp = new Node(k,r->getKey(),0,r->data[0]); delete r; r = temp; r->keyCount++; cout<<"test"<<endl; } </code></pre> <p><strong>end code</strong></p> <pre><code> } else if(k < r->getKey()) { cout<<"left"<<endl; add(k,r->child[Node::L]); } else if(r->keyCount > 1 && k < r->getKey(1)) { cout<<"middle"<<endl; add(k,r->child[Node::M]); } else if(r->keyCount > 1 && k > r->getKey(1)) { cout<<"right"<<endl; add(k,r->child[Node::R]); } else r = new Node(k); } </code></pre> <p>What I'm trying to do is, in the case that there is only 1 out of the 2 keys used in this particular node, replace the current node with a new node which has the keys in the appropriate places (lesser val in key[0], greater val in key[1]) How do I do this properly?</p> <p>My code apparently deletes both the address AND pointer for the old node, but doesn't properly reassign the pointer to the new node.</p> <p><strong>EDIT</strong> updated code. the output is as follows:</p> <pre><code>% p4 Enter pairs consisting of an int and a double. I create a ternary tree, keeping the data in order, by int. Finish entering data by pressing ^d 2 2 add Entering the pair: 2, 2 1 1 add adding second key to current node test Entering the pair: 1, 1 -1 -1 add left add Entering the pair: -1, -1 3 3 add right Segmentation Fault </code></pre> <p><strong>EDIT 2</strong> Here's a link to a zip containing the entire project if you want to look at all the code: <a href="http://sdrv.ms/WSrLfv" rel="nofollow">http://sdrv.ms/WSrLfv</a></p> <p><strong>EDIT 3</strong> More error data - output from gdb on crash</p> <pre><code>Program received signal SIGSEGV, Segmentation fault. 0x08051628 in getData (x=@0x8047554) at testTree.cc:26 26 x[k]=d; Current language: auto; currently c++ </code></pre> <p><strong>EDIT 4</strong> stepping through gdb to the segfault:</p> <pre><code>Breakpoint 1, Tree::add (this=0x8047554, k=3, r=@0x8047554) at tree.cc:58 58 cout<<"add"<<endl; (gdb) n add 61 if(r==NULL){ (gdb) n 65 else if(r->keyCount == 1){ (gdb) n 87 else if(k < r->getKey()) (gdb) n 92 else if(r->keyCount > 1 && k < r->getKey(1)) (gdb) n 97 else if(r->keyCount > 1 && k > r->getKey(1)) (gdb) n 99 cout<<"right"<<endl; (gdb) n right 100 add(k,r->child[Node::R]); (gdb) n Breakpoint 1, Tree::add (this=0x8047554, k=3, r=@0x806416c) at tree.cc:58 58 cout<<"add"<<endl; (gdb) n add 61 if(r==NULL){ (gdb) n 62 r = new Node(k); (gdb) n 107 } (gdb) n 107 } (gdb) n Tree::operator[] (this=0x8047554, index=3) at tree.cc:47 47 return *(locate(index,root)->data); (gdb) n 48 } (gdb) n Program received signal SIGSEGV, Segmentation fault. 0x08051628 in getData (x=@0x8047554) at testTree.cc:26 26 x[k]=d; (gdb) </code></pre>

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