Why do I get a \'Deprecated conversion from string literal to \'char*\'\' warning in C when declaring an array of strings?

Deprecated Conversion from String Literal to 'char*' in C

When declaring an array of strings as shown below:

<code class="cpp">char *colors[4] = {"red", "orange", "yellow", "blue"};</code>

You may encounter the compiler warning: "Deprecated conversion from string literal to 'char*'."

Understanding the Error

This error stems from the fact that the strings provided in "{}" are string literals, defined within the program code itself. By default, string literals are immutable, meaning you cannot modify their contents at runtime, such as by writing to their pointers.

Declaring the array with pointers to characters makes it prone to runtime errors if you attempt to write to the original input ("red", "orange", etc.). This could accidentally modify the original strings, leading to unpredictable results.

Non-Deprecated Solution

To resolve this issue and avoid potential runtime errors, you should declare the array as const pointers to characters.

<code class="cpp">const char *colors[4] = {"red", "orange", "yellow", "blue"};</code>

By adding the const keyword, you ensure that the strings are immutable and will not be unintentionally modified.

Considerations for Editing Values

If you foresee the need to modify the string values at runtime, you can copy the string literals to a separate array or use mechanisms like strtok() to manipulate the individual characters.

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