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POSorting a vector of structs having pointer
 

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  1. POSorting a vector of structs having pointer
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    <p>Below is my code:</p> <pre><code>typedef struct { unsigned page; unsigned slot; } RID; //Below struct has the Key on which I want to apply the sorting struct LeafDataEntry { void *key; RID rid; }; //This is the sorting function I am using bool leadNode_Key_asc( const LeafDataEntry &amp;a, const LeafDataEntry &amp;b){ return strcoll((char *)a.key, (char *)b.key) &gt; 0; //(strcmp((char *)a.key, (char *)b.key) &gt; 0); } int main(){ vector&lt;LeafDataEntry&gt; lde; char a[4] = {'D', 'B', 'C', 'D'}; RID aRID = {0,0}; char b[4] = {'A', 'C', 'B', 'A'}; RID bRID = {0,1}; unsigned size = sizeof(unsigned); lde.resize(2); char *tempPtr = (char *)malloc(8 + sizeof(RID)); memcpy(tempPtr, &amp;size, 4); tempPtr += 4; memcpy(tempPtr, a, 4); tempPtr -= 4; lde[0].key = malloc(8); memcpy(lde[0].key, tempPtr, 8); memcpy(&amp;lde[0].rid, &amp;aRID, sizeof(RID)); memcpy(tempPtr, &amp;size, 4); tempPtr += 4; memcpy(tempPtr, b, 4); tempPtr -= 4; lde[1].key = malloc(8); memcpy(lde[1].key, tempPtr, 8); memcpy(&amp;lde[1].rid, &amp;bRID, sizeof(RID)); std::sort(lde.begin(), lde.end(), leadNode_Key_asc); cout &lt;&lt; "Sorted Data :: " &lt;&lt; endl; for(int j=0; j&lt;2; j++){ cout &lt;&lt; "KEY :: " &lt;&lt; (char *)(lde[j].key); cout &lt;&lt; ", RID ::" &lt;&lt; "{" &lt;&lt; lde[j].rid.pageNum &lt;&lt; ", " &lt;&lt; lde[j].rid.slotNum &lt;&lt; "}"; } return 0; } </code></pre> <p>I want to sort the above lde vector based on the *key value. It's not working with the way given above.</p> <p>NOTE: I cannot change the data types of any of the structs listed above.</p>
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    1. USASingh
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    1. COThat's got to be some of the craziest initialization code I've ever seen. Your sorting code looks fine, assuming that the `key` values are properly null-terminated (but it doesn't look like they are). Make sure your data is what you think it is.
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      1. USAdam Rosenfield
    2. CO@Adam: Thanks...Let me try it out. I wrote this program just for my unit testing..its not exactly what I am gonna use practically.
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      1. USASingh
    3. CO@Adam: I tried ur suggestion of appending the chars above with the '\0'...Still it doesnt works...
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      1. USASingh
 

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