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POSort these elements in descending order?
 

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  1. POSort these elements in descending order?
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    <p>Experimenting with qsort and it runs perfectly for me. I use function pointers throughout the program and some other features I am not used to (i.e. such as void pointers).</p> <p>I want the elements arranged in descending order (i.e. as opposed to ascending order), however. What can I do to achieve this?</p> <p>Here is the code:</p> <pre><code>#include &lt;iostream&gt; #include &lt;cstdlib&gt; // Required for qsort #include &lt;cstring&gt; using std::cout; using std::endl; int compare_strs( const void *arg1, const void *arg2 ); int compare_ints( const void* arg1, const void* arg2 ); int main() { char * shrooms[10] = { "Matsutake", "Lobster", "Oyster", "King Boletus", "Shaggy Mane", "Morel", "Chanterelle", "Calf Brain", "Pig's Ear", "Chicken of the Woods" }; int nums[10] = {99, 43, 23, 100, 66, 12, 0, 125, 76, 2}; // The address of the array, number of elements // the size of each element, the function pointer to // compare two of the elements qsort( (void *)shrooms, 10, sizeof( char * ), compare_strs ); qsort( (void *)nums, 10, sizeof( int * ), compare_ints ); // Output sorted lists for ( int i = 0; i &lt; 10; ++i ) cout &lt;&lt; shrooms[i] &lt;&lt; endl; for ( int i = 0; i &lt; 10; ++i ) cout &lt;&lt; nums[i] &lt;&lt; endl; return 0; } int compare_ints( const void * arg1, const void * arg2 ) { int return_value = 0; if ( *(int *)arg1 &lt; *(int *)arg2 ) return_value = -1; else if ( *(int *)arg1 &gt; *(int *)arg2 ) return_value = 1; return return_value; } int compare_strs( const void * arg1, const void * arg2 ) { return ( _stricmp( *(char **) arg1, *(char **) arg2 ) ); } </code></pre> <p>The program outputs in ascending order (i.e. starting with Calf Brain), but I am trying to get it to start with Shaggy Mane (i.e. descending order). Any help would be much appreciated.</p>
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    1. USWhozCraig
    1. USMrPickle5
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      1. VTUpMod
    1. COSwap the logic in your comparator functions? (and note: your current `int` comparator can simply subtract right from left. the result will be negative if left < right, 0 if they're equal, and positive if left > right.)
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      1. USWhozCraig
    2. COWhy are you using `qsort` in C++?
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      1. USJerry Coffin
    3. CO@WhozCraig Thank you very much or the response. I feel stupid for missing that before I posted my code. I am looking to sort the strings in descending order as well, however. Since it just calls the string compare function, how would I do this?
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