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POC++ Iterators and Linked Lists
 

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    <p>So I'm trying to assign the values of one linked list to another, exterior linked list (not in the current method) using iterators.</p> <pre><code>LIST_ITER i = temp.begin(); while(bLeft != end) { *bLeft = *i; ++i; ++bLeft; } </code></pre> <p>This is only a portion of the code, the iterator i is for the temp list, whereas bLeft and end are the beginning and end (respectively) of the exterior list.</p> <p>This above code, however, is producing a strange error where I get a bunch of strange text (some of it actually says something about Microsoft Windows Compatible etc. etc.) that when run on a Unix machine just gives a Segmentation Fault.</p> <p>EDIT: Here is the code in its entirety:</p> <pre><code>#include &lt;iostream&gt; #include &lt;list&gt; #include &lt;string&gt; #include &lt;iterator&gt; using namespace std; typedef list&lt;string&gt; LIST; // linked list type typedef LIST::size_type LIST_SIZE; // size type for list, e.g., unsigned typedef LIST::iterator LIST_ITER; // iterator type typedef LIST::value_type LIST_CONTAINS; // type in the list, i.e., a string void merge_sort(LIST_ITER beg, LIST_ITER end, LIST_SIZE sz); void merge(LIST_ITER bLeft, LIST_ITER bRight, LIST_ITER end); int main() { LIST l; LIST_CONTAINS v; // Read in the data... while (cin &gt;&gt; v) l.push_back(v); // Merge the data... LIST_ITER i = l.begin(); LIST_ITER iEnd = l.end(); merge_sort(i, iEnd, v.size()); // Output everything... for (; i != iEnd; ++i) { cout &lt;&lt; *i &lt;&lt; '\n'; } system("pause"); } void merge_sort(LIST_ITER beg, LIST_ITER end, LIST_SIZE sz) { if(sz &lt; 2) { return; } else { LIST_SIZE halfsz = (distance(beg, end)/2); //half of list size LIST_ITER i1End = beg; //iterator for the end of the first list advance(i1End, halfsz); //advance to the midpoint i2 = i1End++; //iterator for the beginning of the second list --end;//iterator for the end of the second list merge_sort(beg, i1End, halfsz); //recursively pass first list merge_sort(i2, end, halfsz); //recursively pass second list } merge(beg, i2, end); } void merge(LIST_ITER bLeft, LIST_ITER bRight, LIST_ITER end) { LIST temp; LIST_ITER beg = bLeft; LIST_ITER halfw = bRight; LIST_ITER i = temp.begin(); while(beg != bRight &amp;&amp; halfw != end) { if(*beg &lt; *halfw) { temp.push_back(*halfw); halfw++; } else { temp.push_back(*beg); beg++; } } while(beg != bRight) { temp.push_back(*beg); beg++; } while(halfw != end) { temp.push_back(*halfw); halfw++; } while(bLeft != end) ///HERE IS THE PREVIOUSLY POSTED CODE { *bLeft = *i; ++i; ++bLeft; } } </code></pre>
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    1. USmuttley91
    1. USmuttley91
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    1. COhow are `bLeft` and `end` initialized?
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      1. USAShelly
    2. COProbably you did't allocate enough memory for `temp`, so `++i` will be run out of bounds.
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      1. USMurilo Vasconcelos
    3. COWhat kind of iterators are you using? If the list bLeft is pointing to is empty, the code will break.
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      1. USJosé Tomás Tocino
 

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