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POConstructor function reads from file and stores in linked list
 

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  1. POConstructor function reads from file and stores in linked list
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    <p>I want my program to retain its information within its linked list even after its ended. One way to do this is to read from a file and when done have the destructor save to that same file. I have the code to print to the file within the destructor, however its the reading from my file and storing that has me going nuts. Ive tried numerous ideas but i cant get it to work. Any one have any suggestions on what to add or fix? Beginner programmer here. I have seperate add, remove and clear functions applied.</p> <p>The file im reading from looks like this:</p> <pre><code>HAHA HEHE MEME OEL URNE WUWJ </code></pre> <p>I want to get each string into my linked list. Here is my code:</p> <pre><code>#pragma once #include &lt;string&gt; using namespace std; class StringList; class StringList { private: struct StringListNode { StringListNode *pPrev; string data; StringListNode *pNext; }; public: StringList(); ~StringList(); void addToBottom(string s); void addToTop(string s); void remove(string s); void add(string s); string print(); void clear(); bool isEmpty() {return (pTop==NULL);} private: StringListNode * pTop; StringListNode * pBottom; StringListNode *find(const string &amp;s); }; </code></pre> <p>The functions:</p> <pre><code>#include "StringList.h" #include &lt;string&gt; #include&lt;iostream&gt; #include&lt;fstream&gt; using namespace std; StringList::StringList() { std::ifstream input( "Read.txt" ); pTop = NULL; pBottom = NULL; for( std::string line; getline( input, line ); ) { add(line); } } StringList::~StringList() { ofstream ofs("Read.txt"); StringListNode *next; for (StringListNode *sp = pTop; sp != 0; sp = next) { ofs &lt;&lt; sp-&gt;data &lt;&lt; endl; next = sp-&gt;pNext; delete sp; } } void StringList::add(string s) //adds and places in alphabetical order { if(pTop) { StringListNode *iter = pTop; while (iter &amp;&amp; s &gt; iter-&gt;data) iter = iter-&gt;pNext; if (iter) { // insert before StringListNode *A=new StringListNode; A-&gt;data = s; A-&gt;pNext = iter; A-&gt;pPrev = iter-&gt;pPrev; if (iter-&gt;pPrev) iter-&gt;pPrev-&gt;pNext = A; else pTop = A; iter-&gt;pPrev = A; return; } } // add to bottom addToBottom(s); } StringList::StringListNode *StringList::find(const string &amp;s) //basic search function { StringListNode *sp = pTop; // Search while (sp != 0 &amp;&amp; sp-&gt;data != s) sp = sp-&gt;pNext; return sp; } void StringList::addToTop(string s) //add to top of nodes { if(isEmpty()) { StringListNode * pNewNode; pNewNode = new StringListNode; (*pNewNode).data = s; pTop=pNewNode; pBottom=pNewNode; (*pNewNode).pPrev = NULL; (*pNewNode).pNext = NULL; } else //it's not empty { StringListNode * pNewNode; pNewNode = new StringListNode; (*pNewNode).data = s; (*pNewNode).pNext = pTop; (*pTop).pPrev = pNewNode; (*pNewNode).pPrev =NULL; pTop=pNewNode; } } void StringList::addToBottom(string s) // add to bottom { if(isEmpty()) { StringListNode * pNewNode; pNewNode = new StringListNode; (*pNewNode).data = s; pTop=pNewNode; pBottom=pNewNode; (*pNewNode).pPrev = NULL; (*pNewNode).pNext = NULL; } else { StringListNode * pNewNode; pNewNode = new StringListNode; (*pNewNode).data = s; (*pBottom).pNext = pNewNode; (*pNewNode).pPrev = pBottom; (*pNewNode).pNext =NULL; pBottom=pNewNode; } } string StringList::print() { string result; StringListNode * pCurrent; pCurrent=pTop; while(pCurrent!=NULL) { result+=(*pCurrent).data+"\n"; pCurrent=(*pCurrent).pNext; } return result; } void StringList::clear() { pTop = NULL; pBottom = NULL; } void StringList::remove(string s) { StringListNode *curr = this-&gt;find(s); if (curr-&gt;pPrev != 0) curr-&gt;pPrev-&gt;pNext = curr-&gt;pNext; if (curr-&gt;pNext != 0) curr-&gt;pNext-&gt;pPrev = curr-&gt;pPrev; if (pTop == curr) pTop = curr-&gt;pNext; if (pBottom == curr) pBottom = curr-&gt;pPrev; } </code></pre>
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    1. COWhat exactly is going wrong? You haven't been quite clear.
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    2. COMy program crashes when i try to read from my file. Read my comments within my constructor
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      1. USWestonBuckeye
 

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