void heapsort(int arr[], unsigned int N)   {       unsigned int n = N, i = n/2, parent, child;       int t;            for (;;) { /* Loops until arr is sorted */           if (i > 0) { /* First stage - Sorting the heap */               i--;           /* Save its index to i */               t = arr[i];    /* Save parent value to t */           } else {     /* Second stage - Extracting elements in-place */               n--;           /* Make the new heap smaller */               if (n == 0) return; /* When the heap is empty, we are done */               t = arr[n];    /* Save last value (it will be overwritten) */               arr[n] = arr[0]; /* Save largest value at the end of arr */           }                parent = i; /* We will start pushing down t from parent */           child = i*2 + 1; /* parent's left child */                /* Sift operation - pushing the value of t down the heap */           while (child < n) {               if (child + 1 < n  &&  arr[child + 1] > arr[child]) {                   child++; /* Choose the largest child */               }               if (arr[child] > t) { /* If any child is bigger than the parent */                   arr[parent] = arr[child]; /* Move the largest child up */                   parent = child; /* Move parent pointer to this child */                   //child = parent*2-1; /* Find the next child */                   child = parent*2+1; /* the previous line is wrong*/               } else {                   break; /* t's place is found */               }           }           arr[parent] = t; /* We save t in the heap */       }   }