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POSorting linked list
 

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    <p>I have a slight problem with sorting in linked lists. i have a doubly linked list that needs sorting after intital input, the swap function is what i intend to use, but the problem herein lies that it screws up any header pointers there may be. I cannot sort the list by jusr replacing data as there are too many variables and they can change in the course of development (new variables can be added or deleted)</p> <pre><code>task *taskHeader; struct task{ task *pprev; //large number of variables int number; task *pnext; task(){ pprev = NULL; pnext = NULL; } } //swap function void swap(task *task2, task *task3) task* task1 = task2-&gt;prev; // alias for readability task* task4 = task3-&gt;next; // alias for readability if(task1!=NULL) task1-&gt;next = task3; task3-&gt;prev = task1; task3-&gt;next = task2; task2-&gt;prev = task3; task2-&gt;next = task4; if(task4!=NULL) task4-&gt;prev = task2; } void sort(task *taskHeader){ task *temp = taskHeader; while(temp != NULL){ if(temp-&gt;number &lt; temp-&gt;pnext-&gt;number) swap(temp, temp-&gt;pnext); } } </code></pre> <p>how should i append the swap function to keep my headers intact and not crash when swapping start or end task nodes? currently i do this by adding NULL checks into the swap function to keep the function from going out of bounds and ending up with pointer faults, but is there a better way to solve this?</p> <p>should i just traverse the linked list back til i reach a point where pprev == NULL and change the header to point towards that node?</p>
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    1. COExcept of the constructor, this is C, not C++. A bunch of functions, and a global variable storing the head if the list. As I said, C.
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    2. COthe current code snippet is...but most of the code is in c++ i only used structs to make the linked list, the rest is class based - this is the reason i used a c++ tag as almost everything in c can be compiled within a c++ app
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    3. CONowadays C++ is not a superset of C. Search in SO about this topic. The best example of this: `int new = 0;` Valid C, non-valid C++. **C and C++ are different languages**
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