what is 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);
  }