Simple Min Heap Implementation in C++

#include<iostream>
using namespace std ;
#include<malloc.h>

typedef struct HEAP
{
int *array ;
int capacity ;
int size ;
}mheap ;

mheap* create_heap(int ) ;
mheap* insert_heap(mheap *,int ) ;
int parent(int ) ;
void swap(int *,int *) ;
int delete_position(mheap *,int ) ;
int extract_min(mheap *) ;
void min_heapify(mheap *,int ) ;
int left_child(int ) ;
int right_child(int ) ;
void display_heap(mheap *) ;

int main()
{
mheap *h ;
int no,choice,conti,ele,i ;

cout<<"\n enter the capacity of the heap that needed to be created " ;
cin>>no ;
h=create_heap(no) ;

do
{
cout<<"\n 1. insert an element in the heap " ;
cout<<"\n 2. delete an element from the heap " ;
cout<<"\n 3. extract the minimum element from the heap " ;
cout<<"\n 4. display the elements of the heap (as if in an array)" ;
cout<<"\n\n Please enter your choice " ;
cin>>choice ;
switch(choice)
{
case 1 :cout<<"\n how many elements to insert in the heap " ;
cin>>no ;
cout<<"\n enter elements " ;
for(i=0;i<no;i++)
{
cin>>ele ;
h=insert_heap(h,ele) ;
}
break ;
case 2 :cout<<"\n enter the position of element that needed to be deleted " ;
cin>>no ;
ele=delete_position(h,no) ;
if(ele==-1)
cout<<"\n SORRY !!! heap is empty OR no such position is found in the heap  " ;
else
cout<<"\n element that is deleted from position = "<<no<<" from the heap id = "<<ele ; ;
break ;
case 3 :ele=extract_min(h) ;
if(ele==-1)
cout<<"\n SORRY !!! heap is empty " ;
else
cout<<"\n minimum element in the heap(extracted) = "<<ele ;
break ;
case 4 :display_heap(h) ;
break ;
default :cout<<"\n SORRY !!! wrong choice , please try again " ;
}
cout<<"\n please enter 1 to continue " ;
cin>>conti ;
}while(conti==1) ;
return 0 ;
}

mheap* create_heap(int cap)
{
mheap *h ;
h=(mheap*)malloc(sizeof(mheap)) ;
h->capacity=cap ;
h->size=0 ;
h->array=(int*)malloc(h->capacity*sizeof(int)) ;

return h ;
}

mheap* insert_heap(mheap *h,int data)
{
if(h->capacity==h->size)
{
cout<<"\n SORRY !!! heap is full , No more elements can be inserted " ;
return h ;
}

h->size++ ;
int i ;
i=(h->size)-1 ;
h->array[i]=data ;

while(i!=0&&h->array[parent(i)]>h->array[i])
{
swap(&h->array[i],&h->array[parent(i)]) ;
i=parent(i) ;
}
return h ;
}

int parent(int ele)
{
return (ele-1)/2 ;
}

void swap(int *a,int *b)
{
int temp ;
temp=*a ;
*a=*b ;
*b=temp ;
}

int delete_position(mheap *h,int no)
{
if(h->size==0)
return -1 ;cout<<h->size ;
if(no>h->size)
return -1 ;
if(no==1)
return extract_min(h) ;

int ele ;
ele=h->array[no-1] ;
h->array[no-1]=h->array[h->size-1] ;
h->size-- ;
min_heapify(h,no) ;

return ele ;
}

int extract_min(mheap *h)
{
if(h->size==0)
return -1 ;
if(h->size==1)
{
h->size-- ;
return h->array[0] ;
}

int min ;
min=h->array[0] ;
h->array[0]=h->array[h->size-1] ;
h->size-- ;
min_heapify(h,0) ;

return min ;
}

void min_heapify(mheap *h,int p)
{
int left,right,small ;

left=left_child(p) ;
right=right_child(p) ;
small=p ;

if(left<h->size&&h->array[left]<h->array[p])
small=left ;
if(right<h->size&&h->array[right]<h->array[small])
small=right ;

if(small!=p)
{
swap(&h->array[p],&h->array[small]) ;
min_heapify(h,small) ;
}
}

int left_child(int i)
{
return 2*i+1 ;
}

int right_child(int i)
{
return 2*i+2 ;
}

void display_heap(mheap *h)
{
int i ;
if(h->size==0)
{
cout<<"\n No elemenet present in the heap to diaplay " ;
return ;
}

for(i=0;i<h->size;i++)
cout<<h->array[i]<<" " ;
}