Why can't I assign a value to the class member variable in a bool function that returns const? C++ : <pre><code>bool Car::isEnoughFuel(int miles) const
{
drivableMiles = fuelGauge.getCurrentFuel() * MPG; // Error here
bool status = true;

if (miles &gt; drivableMiles)
    status = false;
return status;
}
</code></pre>

<p>Error: Expression must be a modifiable lvalue.</p>
