I know that it might have been asked billion times, but I could not find any solutions. So, here is my code:
.btn {
  width: 200px;
  height: 45px;
}
.--selected {
  background-color: red;
}<div class="container">
  <button class="btn --selected">uno</button>
  <button class="btn">dos</button>
</div>I need to make that after pressing button it added a --selected class to it, and another one lost it, as if it is a switch between two
Help me out, please
 
     
     
     
     
    