void FindMaxInHeap(int arr[], const int size) {     for (int j = size - 1; j > 0; --j) {       int parent = j / 2;       int child = j;       if (j < size - 1 && arr[j] < arr[j+1]) {         ++child;       }       if (arr[child] > arr[parent]) {         int tmp = arr[child];         arr[child] = arr[parent];         arr[parent] = tmp;       }     }   }   void HeapSort(int arr[], const int size) {     for (int j = size; j > 0; --j) {       FindMaxInHeap(arr, j);       int tmp = arr[0];       arr[0] = arr[j - 1];       arr[j - 1] = tmp;     }   }    int main() {   int arr[] = {2, 5, 3, 12, 6, 21, 8, 1};     int n = sizeof(arr) / sizeof(arr[0]);     HeapSort(arr, n);     for (int j = 0; j < n; ++j) {       printf("%3d",arr[j]);     }     printf("/n");   return 0; }