Граф в виде списка смежности

#include<iostream>
#include<fstream>
#include<cmath>
using namespace std;
struct graph
{
    int x;
    int y;
    double weight;
};
struct node
{
    graph G;
    node* next;
};
void push (node* &p, graph G)
{
    node *temp;
    temp = new node;
    temp->G = G;
    temp->next =p;
    p= temp;


}
void show (node* &p)
{
    while (p)
    {
        cout<<p->G.x <<" "<< p->G.y << " "<<p->G.weight<<endl;
                      p = p->next;
    }
}
void read (node* &p,ifstream &file)
{
    p = NULL;
    graph g;
    while (file >> g.x >>g.y >> g.weight)
    {
        push(p, g);
    }
}
void write (node* p,ofstream &out)
{
    while (p)
    {
        out<<p->G.x <<" "<< p->G.y << " "<<p->G.weight<<endl;
               p = p->next;
    }
}
bool IJustSpentACheck (node* &p,int x,int y)
{
    while (p)
    {
        if ((p ->G.x == x && p->G.y == y)||(p ->G.x == y && p->G.y == x ))
        {
            if (p->G.weight > 0 )
                return true;

        }
        p=p->next;
    }
    return false;
}
int main()
{
    node *list;
    ifstream f ("input.txt");
    ofstream out ("output.txt");
    read(list, f);
    write(list, out);
    int x,y;
    cout<<"Enter x: ";
    cin>>x;
    cout<<"Enter y: ";
    cin>>y;

    if (IJustSpentACheck(list, x, y))
        cout<<"Yes";
    else
        cout<<"No";


}