Pila Insertar valores a la pila

public Pila(){
  this.tamano = 0;
  this.pila = new int[tamano];
}

public void push(int valor){
  int[] aux = new int[this.tamano+1];
  for (int i = 0; i < this.tamano; i++) {
    aux[i] = this.pila[i];
  }
  this.pila = aux;
  this.pila[this.tamano] = valor;
  this.tamano ++;
}