"" is empty, so ""[0] is the nil byte. The code uses "" as an arbitrary address, and ""[1] as that address + 1. This way this-"" gets you 1-based index into t

"" is empty, so ""[0] is the nil byte. The code uses "" as an arbitrary address, and ""[1] as that address + 1. This way this-"" gets you 1-based index into the array. It assumes the compiler dedfuplicates strings, making the behavior of this program undefined.