adjacency list representation of graph gfg code example

Example: adjacency list representation of graph

//adjacency list implementation;addedge,check if edge exist,delete an edge,display
/*            0----->1--------
              |        |     |-->4
              |->2---->|->3---
*/
   
#include <iostream>

using namespace std;
#define v 5
class node
{
public:
    int data;
    node*next;
};
node*adjlist[v];
void init()
{
    for(int i=0;i<v;i++)
    {
        adjlist[i]=NULL;
    }
}
void addedge(int str,int en)
{
    node*temp=new node;
    temp->data=en;
    temp->next=adjlist[str];
    adjlist[str]=temp;
}
void hasedge(int str,int en)
{
    node*temp=new node;
    temp=adjlist[str];
    while(temp!=NULL)
    {
        if(temp->data==en)
        {
            cout<<"yes:";
        }
        temp=temp->next;
    }

}
void remove(int str,int en)
{
    if(adjlist[str]==NULL)
    {
        return;
    }

    if(adjlist[str]->data==en)
    {
        node*temp=new node;
        temp=adjlist[str];
        adjlist[str]=adjlist[str]->next;
        delete temp;
    }
    else
    {
        node *ptr=new node;
        ptr=adjlist[str];
        while(ptr->next!=NULL)
        {
            node*temp=new node;
            if(ptr->next->data==en)
            {

                temp=ptr->next;
                ptr->next=ptr->next->next;
                delete temp;
                break;
            }
            ptr=ptr->next;
        }
    }
}
void display()
{
    for(int i=0;i<v;i++)
    {
        node*temp=new node;
        cout<<"adjlist[]"<<i<<endl;
        temp=adjlist[i];
        while(temp!=NULL)
        {
            cout<<temp->data<<" ";
            temp=temp->next;
        }
        cout<<endl;
    }
}

int main()
{
    init();
    addedge(0,1);
    addedge(0,2);
    addedge(0,3);
    addedge(1,3);
    addedge(1,4);
    addedge(2,3);
    addedge(3,4);
    display();
    hasedge(0,3);
    hasedge(0,4);
    remove(0,1);
    remove(1,4);
    display();
    return 0;
}