First of all , I would like to thank you for your on line program heap sort.2ndly , I would like to know do you mean by lchid=3 and rchild =4 that the position 3(value 4) and the position 4(value 2) in the unorderarray or the real value of the unorder array “1,3,4,5,2” without taking care to the position.pls send me the explanation and the result after one run of outer for loop , which includes 2 loop for each inner for loops With my best regards Nassir H naser@zpu.edu.jo