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POusing vectors with qsort()
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  1. POusing vectors with qsort()
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    copied!<p>I am working on a homework assignment involving vectors using qsort(). I am able to get the code to compile, but I am receiving an error saying <code>Expression: vector subscript is out of range</code> and <code>Expression: Standard C++ Libraries out of range &amp;&amp;0</code> Can anyone help as to where and why my vector subscript is out of range?</p> <pre><code>#include &lt;iostream&gt; #include &lt;fstream&gt; #include &lt;iomanip&gt; #include &lt;string&gt; #include &lt;vector&gt; using namespace std; #include "functions.h" typedef vector&lt; int &gt;::size_type size_t; int main( ) { ifstream ifs = get_ifs( ); sort( ifs ); return 0; } void sort( ifstream &amp;ifs ) { vector&lt; int &gt; vi; int value; while( ifs &gt;&gt; value ) { vi.push_back( value ); } cout &lt;&lt; "unsorted vi:\n" &lt;&lt; vi &lt;&lt; '\n'; qsort( vi ); cout &lt;&lt; "\nsorted vi:\n" &lt;&lt; vi &lt;&lt; '\n'; } void qsort( vector&lt; int &gt; &amp;vi ) { int bot = 0; int top = vi.size() - 1; qsort(vi, bot, top); } void qsort( vector&lt; int &gt; &amp;vi, size_t low, size_t high ) { if (low &lt; high) { int split = partition(vi, low, high); qsort(vi, low, split-1); qsort(vi, split+1,high); } else { return ; } } size_t partition( vector&lt;int&gt;&amp; vi, size_t low, size_t high ) { int pivot = vi[high]; int bottom = low - 1; int top = high; bool notdone = true; while(notdone) { while(notdone) { bottom += 1; if (bottom == top) { notdone = false; break; } if (vi[bottom] &gt; pivot) { vi[top] = vi[bottom]; break; } } while (notdone) { top = top-1; if (top == bottom) { notdone = false; break; } if (vi[top] &lt; pivot) { vi[bottom] = vi[top]; break; } } } vi[top] = pivot; return top; } void print_vec( const vector&lt; int &gt; &amp;vi, size_t n, size_t t ) { cout &lt;&lt; vi; for( size_t i = 0; i &lt; t; ++i ) { cout &lt;&lt; setw( 3 ) &lt;&lt; vi[ i ] &lt;&lt; ' '; } } ostream &amp;operator &lt;&lt;( ostream &amp;out, const vector&lt; int &gt; &amp;vi ) { vector&lt; int &gt;::const_iterator iter; for( iter = vi.begin( ); iter != vi.end( ); ++iter ) { out &lt;&lt; setw( 3 ) &lt;&lt; *iter &lt;&lt; ' '; } return out; } ifstream get_ifs( ) // get input file stream { string filename; // input file name cerr &lt;&lt; "name of file to read from? "; cin &gt;&gt; filename; ifstream ifs( filename, ifstream::in ); if( ! ifs ) // cannot open file infilen { cerr &lt;&lt; "cannot open input file '" &lt;&lt; filename &lt;&lt; "'\n"; exit( 1 ); } return ifs; // return input file stream } </code></pre>
 

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