Why Choose `const char * const` over `const char *` in C ?

const char * const versus const char * in C

A common question arises when examining code utilizing constant character pointers: why use const char * const over const char *? Let's explore this using an example code:

<code class="cpp">void print_string(const char * the_string)
{
    cout <p>Here, two options arise for the parameter to print_string: const char * and const char * const. The distinction between them lies in their pointer mutability.</p>
<ul>
<li>
<strong>const char *:</strong> While the string it points to is immutable, the pointer itself can be modified to refer to a different string.</li>
<li>
<strong>const char * const:</strong> Both the string and the pointer are immutable, ensuring that the parameter cannot be altered within print_string.</li>
</ul>
<p>Why does both options work in practice? In the example, neither the string nor the pointer is modified in print_string. The relevance of const char * arises when attempting to change the pointed-to string. </p>
<p>Consider the following variations:</p>
<ul>
<li>
<strong>char* the_string:</strong> Pointer and value mutable.</li>
<li>
<strong>const char* the_string:</strong> Value mutable, pointer immutable.</li>
<li>
<strong>char* const the_string:</strong> Value mutable, pointer immutable.</li>
<li>
<strong>const char* const the_string:</strong> Value and pointer immutable.</li>
</ul>
<p>In the provided example, const char * const would be a more appropriate choice to prevent unintended modification of the_string within print_string. It serves as an additional safeguard against potential errors.</p></code>

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