Heap Sort Program

#include<iostream .h> #include<conio .h> int heapsize,length; void exchange(int &a,int &b) { int temp; temp=a; a=b; b=temp; } void maxheapify(int a[],int i) { int l,r,largest,temp; l=2*i; //left[i] r=2*i+1; //right[i] if(l<=heapsize&&a[l]>a[i]) largest=l; else largest=i; if(r<=heapsize&&a[r]>a[largest] ) largest=r; if(largest!=i) { exchange(a[i],a[largest]); maxheapify(a,largest); } } void buildmaxheap(int a[]) { heapsize=length; for(int i=length/2;i>=1;i--) maxheapify(a,i); } void heapsort(int a[]) { buildmaxheap(a); for(int i=length;i>=2;i--) { exchange(a[1],a[i]) ; heapsize-=1; maxheapify(a,1); } } void main() { clrscr(); int *a,n; cout<<"\nEnter the no of element you want(max 20):"; cin>>n; length=n; a=new int[n+1]; //DYNAMICALLY INITIALISE ARRAY,AS ARRAY MUST START FROM INDEX 1 SO SIZE IS (N+1) cout<<"\nEnter the elements:\n"; for(int i=1;i<=n;i++) cin>>a[i]; heapsort(a); cout<<"\nSorted Array is:\n"; for(i=1;i<=n;i++) cout<<a[i]<<" "; getch(); }