what is navi class bootstrap code example

Example 1: nav bootstrap

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNav">
    <ul class="navbar-nav">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricing</a>
      </li>
      <li class="nav-item">
        <a class="nav-link disabled" href="#">Disabled</a>
      </li>
    </ul>
  </div>
</nav>

Example 2: bootstrap nav

<ul class="nav nav-tabs" id="myTab" role="tablist">
  <li class="nav-item">
    <a class="nav-link active" id="home-tab" data-toggle="tab" href="#home" role="tab" aria-controls="home" aria-selected="true">Home</a>
  </li>
  <li class="nav-item">
    <a class="nav-link" id="profile-tab" data-toggle="tab" href="#profile" role="tab" aria-controls="profile" aria-selected="false">Profile</a>
  </li>
  <li class="nav-item">
    <a class="nav-link" id="contact-tab" data-toggle="tab" href="#contact" role="tab" aria-controls="contact" aria-selected="false">Contact</a>
  </li>
</ul>
<div class="tab-content" id="myTabContent">
  <div class="tab-pane fade show active" id="home" role="tabpanel" aria-labelledby="home-tab">...</div>
  <div class="tab-pane fade" id="profile" role="tabpanel" aria-labelledby="profile-tab">...</div>
  <div class="tab-pane fade" id="contact" role="tabpanel" aria-labelledby="contact-tab">...</div>
</div>