String quicksort in c++ : <p>I'm trying to implement alphabet sorting using quick sort in c++ but I'm not able to do so :( </p>

<p>Below is my code :</p>

<pre><code>#include &lt;iostream&gt;
#include &lt;string&gt;
using namespace std;

int partition(string &amp;str, int start, int end){
    int pivot = str[end-1];
    int i = start;
    for(int j=start; j&lt;end-1 ; j++){
        if(str[j]&lt;=pivot){
            swap(str[j], str[i]);
            i++;
        }
    }
    swap(str[i], str[end]);
    return i;
}

void quicksort(string &amp;str, int start, int end){
    if(start&lt;end){
        int pIndex = partition(str, start, end);

        quicksort(str, start, pIndex-1);
        quicksort(str, pIndex+1, end);
    }
}
int main()
{
    int t,k, end, start;
    string str;

    cin&gt;&gt;t;
    for(k=0;k&lt;t;k++){
        cin&gt;&gt;str;
        end = str.size();

        quicksort(str, 0, end);
        for(int l=0; l&lt;end; l++){
            cout&lt;&lt;str[l];
        }
        cout&lt;&lt; "\n";
    }


    return 0;
}
</code></pre>

<p>Please take a look at it and help me where I'm doing it wrong? :(</p>

<p>Thanks in advance.</p>
