Answer to Question #233665 in C++ for David

Question

The function below should insert a value as the head of a given UNORDERED linked list. Be
careful to first search for the given value. The value is inserted only if it does not exist in the
list. If the value exists, the function does nothing. Use Linked list implementation of Task 1 to
make this function run. Write down the code of insert function run the code, take snap shot
and paste it in your document.
struct Node{
int data;
Node* next;
};
The function prototype is given. Implement the function.
void insert(Node* &head, int value);

Answer 1

#include<bits/stdc++.h>
using namespace std;


 class Node
 {
     public:
      
       int data;
        Node* nextNode;
 };
 bool searchElement(Node*node, int data)
 {
     Node* curr=node;
     
      while(curr!=NULL)
      {
          if(curr->data==data)
          {
              return true;
          }
          
          curr=curr->nextNode;
      }
      
      return false;
 }
 void display(Node *head){
 	while(head !=NULL){
 		cout<<head->data<<"=>  \t";
 		head = head->nextNode;
	 }
 }
 void insert(Node** head, int data)
 {
     Node* temp= new Node();
     
     temp->data=data;
     
     temp->nextNode=*head;
     
     *head=temp;
 }
 
 
 int main()
 {
     Node* head=NULL;
     
     int data;
     
      cout<<"Enter data :"<<endl;
       cin>>data;
       
        insert(&head,21);
        insert(&head,32);
        insert(&head,45);
        insert(&head,56);
        if(searchElement(head,data)==1){
        	cout<<"The element already exist\n";
		}
		else{
			cout<<"Element inserted successfully\n";
			insert(&head,data);
		}
					cout<<"The list is: \n";


        display(head);
 }