Constant expressions in array declarations
arrays, c++, constexpr
Solution
Your code is not actually legal C++. Some compilers allow variable-length arrays as an extension, but it's not standard C++. To make GCC complain about this, pass `-pedantic`. In general, you should always pass at least these warning flags go GCC:
-W -Wall -Wextra -pedantic
Problem
C++ Primer says that Array dimension must be known at compile time, which means that the dimension must be a constant expression A separate point is made that ``` unsigned count = 42; // not a constant expression constexpr unsigned size = 42; // a constant expression ``` I would, then expect for the following declaration to fail ``` a[count]; // Is an error according to Primer ``` And yet, it does not. Compiles and runs fine. What is also kind of strange is that `++count;` subsequent to array declaration also causes no issues. Program compiled with `-std=c++11` flag on `g++4.71` Why is that?