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POWhy is this string changed?
 

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    <p>I have the following code, so far, I want to check if a file name is already in the linked list <code>fileList</code> (or <code>flist</code>). according to the output, the string saved in the first Node was changed somewhere in <code>Node* getFileName(Node *&amp;flist)</code> How did this happen? Also, is there anything else that I'm doing is wrong or not safe regarding pointers of Node and strings?</p> <p>output:</p> <pre> in main: file4.txt start of process: file4.txt file4.txt mid of process: file4.txt" in contains, fileName in node: file4.txt" in contains, target file name: file4.txt end of process: file4.txt" 0 no recursive call </pre> <p>code:</p> <pre><code>struct Node { string fileName; Node *link; }; /* * */ bool contains (Node *&amp;flist, string &amp;name) { Node *tempNode = *&amp;flist; while (tempNode != 0) { cout &lt;&lt; "in contains, fileName in node: " &lt;&lt; flist-&gt;fileName &lt;&lt; endl; cout &lt;&lt; "in contains, target file name: " &lt;&lt; name &lt;&lt; endl; if ((tempNode-&gt;fileName) == name) { return true; } else { tempNode = tempNode-&gt;link; } } return false; } /* * */ Node* getLastNode (Node *&amp;flist) { Node *tempNode = *&amp;flist; while (tempNode != 0) { tempNode = tempNode-&gt;link; } return tempNode; } /* * */ string getFileName(string oneLine) { char doubleQuote; doubleQuote = oneLine[9]; if (doubleQuote == '\"') { string sub = oneLine.substr(10); //getting the file name string::size_type n = sub.size(); sub = sub.substr(0,n-1); cout &lt;&lt; sub &lt;&lt; endl; return sub; } return NULL; } /* * */ void process( istream &amp;in, ostream &amp;out, Node *&amp;flist ) { cout &lt;&lt; "start of process: " &lt;&lt; flist-&gt;fileName &lt;&lt; endl; string oneLine; //temp line holder while (getline(in, oneLine)) { // cout &lt;&lt; oneLine &lt;&lt; endl; string::size_type loc = oneLine.find("#include",0); if (loc != string::npos) { //found one line starting with "#include" string name; name = getFileName(oneLine); cout &lt;&lt; "mid of process: " &lt;&lt; flist-&gt;fileName &lt;&lt; endl; bool recursive; recursive = contains(flist, name); cout &lt;&lt; "end of process: " &lt;&lt; flist-&gt;fileName &lt;&lt; endl; cout &lt;&lt; recursive &lt;&lt; endl; if (recursive) { //contains recursive include cerr &lt;&lt; "recursive include of file " &lt;&lt; name &lt;&lt; endl; exit(-1); } else { //valid include cout &lt;&lt; "no recursive call" &lt;&lt; endl; }//else }//if }//while }//process /* * */ int main( int argc, char *argv[] ) { istream *infile = &amp;cin; // default value ostream *outfile = &amp;cout; // default value Node* fileList; switch ( argc ) { case 3: outfile = new ofstream( argv[2] ); // open the outfile file if ( outfile-&gt;fail() ) { cerr &lt;&lt; "Can't open output file " &lt;&lt; argv[2] &lt;&lt; endl; exit( -1 ); } // FALL THROUGH to handle input file case 2: infile = new ifstream( argv[1] ); // open the input file if ( infile-&gt;fail() ) { cerr &lt;&lt; "Can't open input file " &lt;&lt; argv[1] &lt;&lt; endl; exit( -1 ); } else { Node aFile = {argv[1], 0}; fileList = &amp;aFile; cout &lt;&lt; "in main: " &lt;&lt; fileList-&gt;fileName &lt;&lt; endl; } // FALL THROUGH case 1: // use cin and cout break; default: // too many arguments cerr &lt;&lt; "Usage: " &lt;&lt; argv[0] &lt;&lt; " [ input-file [ output-file ] ]" &lt;&lt; endl; exit( -1 ); // TERMINATE! } processOneFile (*infile, *outfile, fileList); // do something if ( infile != &amp;cin ) delete infile; // close file, do not delete cin! if ( outfile != &amp;cout ) delete outfile; // close file, do not delete cout! } </code></pre>
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    1. USbobbymcr
    1. USderrdji
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      1. POWhy is this string changed?
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    1. COHave you tried stepping through your code with a debugger? It should prove more successful than using `print` statements to show which statement changes your data.
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      1. USSteve Guidi
    2. COCould you please provide us with the files needed to compile this?
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      1. USHåkon
    3. COI'd recommend also to use std::set to maintain file names instead of self-crafted list.
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      1. USdimba
 

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