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POC++Can't find error, double free or corruption (fasttop)
 

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  1. POC++Can't find error, double free or corruption (fasttop)
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    <p>I am getting the following output from my program:</p> <pre><code>$ ./list Enter list 1: [1,2,3,4] [ Enter list 2: [2,5,8,0] [ [1,2,3,4] [1,2,3,4] *** Error in `./list': double free or corruption (fasttop): 0x0000000000f85100 *** ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x80a46)[0x7fa0368d6a46] ./list[0x400d5f] ./list[0x400c62] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7fa036877ea5] ./list[0x400ae9] ======= Memory map: ======== 00400000-00402000 r-xp 00000000 ca:01 410613 /home/ubuntu/list </code></pre> <p>...</p> <pre><code>ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall] the endAborted (core dumped) </code></pre> <p>This is what I have in main:</p> <pre><code>int main(){ pennlist::List l1,l2; cout&lt;&lt;"Enter list 1:\t"; cin&gt;&gt;l1; cout&lt;&lt;"Enter list 2:\t"; cin&gt;&gt;l2; cout&lt;&lt;l1&lt;&lt;endl&lt;&lt;l2&lt;&lt;endl; cout&lt;&lt;"the end"; } </code></pre> <p>And this this is the overloaded >> operator. </p> <pre><code>istream&amp; operator &gt;&gt;(istream&amp; ins, List&amp; write_me){ char discard; write_me.head = new node; write_me.current = write_me.head; node* temp = write_me.head; ins&gt;&gt;discard;//get [ cout&lt;&lt;discard&lt;&lt;endl; while(discard != ']'){ ins&gt;&gt;temp-&gt;data; write_me.count += 1; temp-&gt;to_tail = new node; temp-&gt;to_head = temp; temp = temp-&gt;to_tail; ins&gt;&gt;discard; //get , or ] } write_me.tail = temp; temp = NULL; return ins; } </code></pre> <p>I have overloaded the =, ~ and copy ctr as well and get the same error before and after adding these functions.</p> <p>I can't figure out how to resolve this error, please help.</p> <p>EDIT</p> <pre><code>Here is the code for the destructor: ~List{ delete head; delete current; delete tail; } </code></pre>
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    1. USMatt Pennington
    1. USMatt Pennington
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    1. COThe only time I call delete is in pennlist::List::~List { delete head; delete current; delete tail; } hmm. Would delete head; and delete current; conflict if they are pointing to the same location?
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      1. POC++Can't find error, double free or corruption (fasttop)
      1. USMatt Pennington
    2. COThe answer is yes. Thank you!
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      1. POC++Can't find error, double free or corruption (fasttop)
      1. USMatt Pennington
    3. COYou should add the code that was causing the problem to your OP, and then answer your own question so others can learn from the solution. Also, might I recommend Valgrind (http://valgrind.org/) as a good tool for tracking down memory issues like this (and other, more complicated problems like memory leaks).
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      1. POC++Can't find error, double free or corruption (fasttop)
      1. USCmdrMoozy
 

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