Understanding variable-length arrays

A Variable-Length Array (VLA) is an array whose size is not known until runtime. The first set of arrays declared earlier have fixed length declarations. The second set of arrays are VLA declarations. A VLA declaration is like a fixed-length declaration, except that the array size is specified by a non-constant expression. Here, non-constant refers to a non-literal variable value.

Remember that a const type is a variable whose value is determined at runtime, so even though it cannot be changed once initialized, it is still considered a variable and not a literal constant. When a VLA declaration is encountered, the size expression is evaluated and the array is created with the resultant length. This length must be a positive integer. Once created, the size of a VLA is fixed and cannot change, just as with constant-length arrays.

So, note that the variable in a VLA means that the array size is defined by some variable value and not that the...