Here are some potential titles for your article, formatted as question-answer pairs: **Option 1 (Focus on the Error):** * **Why am I getting an \"expected constant expression\" error when d

Expected Constant Expression Error in Array Size

In C , an array declaration requires a constant size. When an attempt is made to declare an array with a non-constant expression, a "expected constant expression" error occurs.

Consider the following code snippet:

<code class="cpp">int size = 100;
float x[size][2]; // Error</code>

In this example, size is a runtime value, making it a non-constant expression. Therefore, the compiler cannot determine the size of the array at compile-time, resulting in the error.

Resolution

To resolve this issue, use a data structure that supports dynamic sizing, such as a std::vector:

<code class="cpp">std::vector<std::array<float, 2>> x(size);</code>

Alternatively, you can use new to allocate memory for the array:

<code class="cpp">float (*px)[2] = new float[size][2];</code>

Remember to delete[] px after use to free the memory.

Other Options

If you don't have access to modern C features like std::vector:

• Use a vector of std::pair
• Create your own array type with dynamic sizing using templates

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