Evan tho i use corecet traverse condition while (p != NULL) the program does additinoal rotation printing nothing usefull,the issue is in case 4 of the switch in displayproduct function called from unicDispaly function, here is the cut down code:

#include <iostream>
using namespace std;

struct product {
    char name[50];
    int quantity;
    };
struct productlist {
   product x;
    productlist* next;
};


struct drug {
    int Unum;
    char label[50];
    float Uprice;
    char category[50];
    productlist* Lproduct;
};

typedef struct tree {
    drug x;  // Left child (pointer to tree)
    tree* Lch;
    tree* Rch;
} tree;
productlist* createproductlist(product x){
productlist*l=new productlist;
l->x=x;
l->next=NULL;
return l ;


}
tree* createdrugtree(drug x) {
    tree* t = new tree;        // Dynamically allocate memory for the tree
    t->x = x;                  // Initialize the drug element
    t->Lch = NULL;             // Set left child as NULL
    t->Rch = NULL;             // Set right child as NULL
    return t;                  // Return the tree
}



product createP(){
product x;
cout << "Enter product namen";
cin>>x.name;
cout << "Enter product quantityn";
cin>>x.quantity;
return x;
}


}
bool searchUnic(tree* &t,int unum){
bool found=false;
    while(t!=NULL){
  if (t->x.Unum == unum) {
  found=true;
  }
    else if (unum < t->x.Unum) t=t->Lch;
     else if(unum>=t->x.Unum)t=t->Rch;
     if(found==true){
        break;
     }
    }
   if(found==false){
    cout<<"drug not foundn";
return found;
   }
   return true;
}


}
void displayproduct(tree* t){
    if (t->x.Lproduct == NULL) {
        cout << "No products associated with this drug.n";

    }
    cout << "Product details:n";
    productlist* p = t->x.Lproduct;
    while (p != NULL) {
            
        cout << "Name: " << p->x.name << ", Quantity: " << p->x.quantity << "n";
        p = p->next;
    }
}


void unicDispaly(tree* t,int unum){
tree* T=t;
searchUnic(T,unum);
    cout<<"the lable:"<<T->x.label<<"n";
    cout << "the drug unit Price:";
    cout << T->x.Uprice<<"n";
    cout << "the drug Category:";
    cout <<T->x.category<<"n";
    cout<<"the products:";
    displayproduct(T);
}



int main() {
tree* t=NULL;

    int choice;
 do {
        cout << "nPharmaceutical Management Systemn";
        cout << "1. Add Drugn";
        cout << "2. Add Products to Drugn";
        cout << "3. Display All Drugsn";
        cout << "4. Search for a Drugn";
        cout << "0. Exitn";
        cout << "Enter your choice: ";
        cin >> choice;
        int unum;
 switch(choice){
case 1:
  addTree(t,createD());
break;
case 2:

    cout<<"enter unic number:";
cin>>unum;
  addproduct(t,unum);
  break;
case 3:
    cout<<"the tree:";
    display(t);
    break;
case 4:
     cout<<"enter unic number:";
cin>>unum;
unicDispaly(t,unum);
cout<<"the drug:";
 }


 }while(choice!=0);
    return 0;
}

here is the console

Pharmaceutical Management System
1. Add Drug
2. Add Products to Drug
3. Display All Drugs
4. Search for a Drug
0. Exit
Enter your choice: 1
Enter drug unique number
1
Enter drug lable
1
Enter drug unit Price
1
Enter drug Category
1

Pharmaceutical Management System
1. Add Drug
2. Add Products to Drug
3. Display All Drugs
4. Search for a Drug
0. Exit
Enter your choice: 2
enter unic number:1
Enter product name
11
Enter product quantity
11

Pharmaceutical Management System
1. Add Drug
2. Add Products to Drug
3. Display All Drugs
4. Search for a Drug
0. Exit
Enter your choice: 4
enter unic number:1
the lable:1
the drug unit Price:1
the drug Category:1
the products:Product details:
Name: 11, Quantity: 11
Name: , Quantity: 0

Process returned -1073741819 (0xC0000005)   execution time : 22.681 s
Press any key to continue.

so i am biasicly trying to do a pharmaceutical drug managing program for this assiment and the parts I’m having trouble with is displaying the elements of a linked list , so I set the exiting condition for the while loop to while (p != NULL),but it still run 1 time after p=null