title: randomized_quicksort
body: <p>this code does not show me any output</p>
  
  <pre><code>#include &lt;cstdlib&gt;
  #include &lt;iostream&gt;
  using namespace std;
  
  int partition(int a[], int left, int right) {
      int i = left;
      int j = right;
  
      int temp;
      int pivot = a[left];
  
      while(i &lt;= j) {
          while(a[i] &lt; pivot)
               i++;
  
          while(a[j] &gt; pivot)
              j--;
              if(i&gt;j) break;
  
              if (i&lt;j){
                  temp = a[i];
                  a[i] = a[j];
                  a[j] = temp;
                  i++;
                  j--;
              }
      }
      return i;
  }
  
  int randomized_partition(int a[], int left, int right){
      int t = left + rand() % (right - left + 1);
  
      std::swap(a[right], a[t]);
      return partition(a, left, right);
  }
  
  void randomized_quicksort(int a[], int l, int r){
      if(l&gt; = r) return;
  
      int q = randomized_partition(a, l, r);
      randomized_quicksort(a, l, q-1);
      randomized_quicksort(a, q+1, r);
  }
  
  int main(){
      int a[] = {12, 6, 4, 7, 9, 10, 11, 14, 13, 19, 18, 21, 20};
      int n = sizeof(a) / sizeof(n);
      randomized_quicksort(a, 0, n-1);
  
      for (int i = 0; i &lt; n; i++){
          cout &lt;&lt; a[i] &lt;&lt; "  " &lt;&lt; endl;
      }
      return 0;
  }
  </code></pre>
  
  <p>it is randomized_quicksort    from introduction in algorithms third edition and   please help </p>