how to implement stack in java code example

Example 1: java stack

// construct with non-primative elements only!
Stack<String> stack = new Stack<String>();

// to add a value to the top of the stack:
stack.push("Hello");

// to return and remove a value from the top:
String top = stack.pop();

// to return a value without removing it:
String peek = stack.peek();

Example 2: stack class in java

import java.util.Stack;
class Main {
    public static void main(String[] args) {
        Stack<String> animals= new Stack<>();
        // Add elements to Stack
        animals.push("Dog");
        animals.push("Horse");
        // Remove element from Stack
      	animals.pop();
      	// Access element from top of Stack
      	animals.peek();
    }
}

Example 3: stack implementation

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;
}