How Can C Create Variable-Sized Arrays at Runtime?

Variable-Sized Arrays in C at Runtime

Variable-sized arrays are a feature introduced in C99. Unlike traditional C arrays, their size can be determined at runtime.

In the provided code snippet:

int main(int argc, char **argv)
{
    size_t size;
    cin >> size;
    int array[size];
    // ...
}

The size of the array array is not specified at compile time but rather determined by user input at runtime. This is permissible in C99 and supported by the provided compiler, most likely GCC.

It's important to note that the memory for the array is allocated on the stack, similar to fixed-size arrays. This differs from dynamic memory allocation techniques like malloc and new. Hence, the compiler allocates the array directly on the stack, avoiding the overhead of heap operations.

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