20) Write a cpp program to demonstrate the Hashing
#include<iostream>
#include<stdlib.h>
using namespace std;
#define max 100
typedef struct list
{
 int data;

struct list *next;
}node;
node *ptr[max],*root[max],*temp[max];
class dic
{
 public:
int index;

dic()

{

 index=-1;

 for(int i=0;i<=max;i++)

 {

 root[i]=NULL;

 ptr[i]=NULL;

 temp[i]=NULL;

 }

 }
void insert(int key)

 {

 index=int(key%max);

 ptr[index]=new node;

 ptr[index]->data=key;

 if(root[index]==NULL)

 {

 root[index]=ptr[index];

 root[index]->next=NULL;

 temp[index]=ptr[index];

 }

 else

 {

 temp[index]=root[index];

 while(temp[index]->next!=NULL)

 temp[index]=temp[index]->next;

 temp[index]->next=ptr[index];

 }
void search(int key)
 {

 int flag=0;

 index=int(key%max);

 temp[index]=root[index];

 while(temp[index]->data==key)

 {

 if(temp[index]->data==key)

 {

 cout<<"\n search key is found";

 flag=1;

 break;

 }

 else

 temp[index]=temp[index]->next;

 }

 if (flag=0)

 cout<<"searched key not found";
 }
void delete_ele(int key)
{

index=int(key%max);

temp[index]=root[index];

while(temp[index]->data!=key&&temp[index]!=NULL)

{

 ptr[index]=temp[index];

 temp[index]=temp[index]->next;

}

 ptr[index]->next=temp[index]->next;

 cout<<"\n"<<temp[index]->data<<"has been deleted";

 temp[index]->data=-1;

 temp[index]=NULL;

 free(temp[index]);
 }
};
int main()
{
 int val,ch,n,num;
 char c;
 dic d;
 do
 {
 cout<<"\n Menu \n1.create \n2.search \n3.delete \n4.exit";
 cout<<"\n enter your choice:";
 cin>>ch;
switch(ch)
 {
 case 1:
cout<<"\n enter the no of elements to be instered";

cin>>n;

cout<<"enter the elements to be inserted";

for(int i=0;i<n;i++)

{

 cin>>num;

 d.insert(num);

 }

 break;
 case 2:
cout<<"enter the elements to be serached";

cin>>n;

 d.search(n);

 break;
 case 3:
cout<<"enter the elements to be deleted";

cin>>n;

d.delete_ele(n);

break;
 case 4:
exit(0);
 default:
cout<<"invalid choice";
 }
 } while(ch<=4);
}