reference to an array of size determined at run-time

Question

I tried to find this but can't find any. I know I can create a reference to an array variable:

int x[10] = {}; int (&y)[10] = x;

However, in the case that the array size is not known at compile time, like in the following code:

const int n = atoi( string ); //the string is read from a text file at run time.
int x[n] = {}; int (&y)[n] = x; //this generates a compiling error.

Even if int n is declared const, as long as n is not known at compile time, the reference is invalid. The compiler will say something like this: reference to type 'int [n]' cannot bind to a value of unrelated type 'int [n]'. Anyone has any idea about how to fix this? Thanks in advance.

Answer 1

Runtime-length arrays are a C99 feature and do not exist in standard C++. They're present as an extension on some C++ compilers, but don't mix well with C++ features, like references and templates.

You should probably use a vector.

Answer 2

The feature of declaring arrays dynamically like shouldn't be used in C++. Not all compilers support it. Consider using the STL containers instead. Like std::vector<int>