Bootstrap navigation with Codeigniter base_url function calls.

nav.php

<nav class="navbar navbar-expand-lg bg-primary">
	<div class="container">
		<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#mainNav" aria-expanded="false" aria-label="Toggle navigation"><span class="navbar-toggler-icon"><i class="fas fa-bars"></i></span></button>
		<div class="collapse navbar-collapse" id="mainNav">
			<div class="navbar-nav">
				<ul class="navbar-nav mr-auto mt-2 mt-lg-0">
					<li class="nav-item">
						<a class="nav-link" href="<?php echo base_url(); ?>">Home</a>
					</li>
						<li class="nav-item">
							<a class="nav-link" href="<?php echo base_url(); ?>user/profile">Profile</a>
						</li>
						<li class="nav-item">
							<a class="nav-link" href="<?php echo base_url(); ?>auth/logout">Logout</a>
						</li>
						<li class="nav-item">
							<a class="nav-link" href="<?php echo base_url(); ?>auth/register">Register</a>
						</li>
						<li class="nav-item">
							<a class="btn btn-info" href="<?php echo base_url(); ?>auth/login">Login</a>
						</li>
				</ul>
			</div>
		</div>
	</div>
</nav>