what is the stack code example

Example 1: stack

typedef struct Nodo{
   Elem val;
   struct Nodo *next;
} *Stack;
Stack Empty(){return NULL;}
bool IsEmpty(Stack a){return a==NULL;}
Elem Top(Stack a){return a->val;} 
Stack Pop(Stack l){return l->next;}
Stack Push(Elem x,Stack res){
    Stack nuevo=(Stack)malloc(sizeof(struct Nodo));
    nuevo->val=x;
    nuevo->next=res;
    return nuevo;
}

Example 2: stack

Future _handleNotification(
    Map message, bool dialog) async {
    var data = message['data'] ?? message;
    String notificationTitle = data['YOUR_KEY']; // here you need to replace YOUR_KEY with the actual key that you are sending in notification  **`"data"`** -field of the message. 
    String notificationMessage = data['YOUR_KEY'];// here you need to replace YOUR_KEY with the actual key that you are sending in notification  **`"data"`** -field of the message. 

    // now show the Dialog
    Utils().showMessageDialog(context, notificationTitle,notificationMessage);
  }

Example 3: what is full stack

1. create a data (a customer account) on UI
2. send request from API and verify data is 
matching with UI (you reach your database
through API, it is credible as much as 
your API software is credible)
3. send SQL queries using JDBC get request
to database and verify data is
matching with post request