Question

Write a program for Heap sort. Your program should read from an input file data3.txt
and write to an output file output3.txt. The input/output format is identical to
programming assignment 1.
For this assignment you cannot use STL. Take the maximum size of array to be 100.
Follow all instructions in programming assignment 1.

Need help code in C++.

Answer 1

#include <iostream>
using namespace std;

void MAX_HEAPIFY(double a[], int i, int n)
{
int l,r,largest;
double loc;
l=2*i;
r=(2*i+1);
if((l<=n)&&a[l]>a[i])
largest=l;
else
largest=i;
if((r<=n)&&(a[r]>a[largest]))
largest=r;
if(largest!=i)
{
loc=a[i];
a[i]=a[largest];
a[largest]=loc;
MAX_HEAPIFY(a, largest,n);
}
}
void BUILD_MAX_HEAP(double a[], int n)
{
for(int k = n/2; k >= 1; k--)
{
MAX_HEAPIFY(a, k, n);
}
}
void HEAPSORT(double a[], int n)
{

BUILD_MAX_HEAP(a,n);
int i;
double temp;
for (i = n; i >= 2; i--)
{
temp = a[i];
a[i] = a[1];
a[1] = temp;
MAX_HEAPIFY(a, 1, i - 1);
}
}

int main()
{
int n;
cout<<"Enter the size of the array"<<endl;
cin>>n;
double a[n];
cout<<"Enter the elements in the array"<<endl;
for (int i = 1; i <= n; i++)
{
cin>>a[i];
}
HEAPSORT(a, n);
cout<<":::::::SORTED FORM::::::"<<endl;
for (int i = 1; i <= n; i++)
{
cout<<a[i]<<endl;
}
}

NOTE

input formate

first line of input take size of array n

next n line contain element of array