All the talk about macros this week inspired me to share this macro that **Lance Robinson** came across while maintaining a C-based system at his company. What I really appreciate about this code, well, aside from the fact that it's built into ctype.h and, aside from the fact that it has nests twenty-six ternary operators, is its very subtle bug ... can you spot it?

// Macro to normalize table names // (all of them will be stored in upper case ) #define TO_UPPER( x )( \ ( 'a' == ( x ) ) ? 'A' : \ ( 'b' == ( x ) ) ? 'B' : \ ( 'c' == ( x ) ) ? 'C' : \ ( 'd' == ( x ) ) ? 'D' : \ ( 'e' == ( x ) ) ? 'E' : \ ( 'f' == ( x ) ) ? 'F' : \ ( 'g' == ( x ) ) ? 'G' : \ ( 'h' == ( x ) ) ? 'H' : \ ( 'i' == ( x ) ) ? 'I' : \ ( 'j' == ( x ) ) ? 'J' : \ ( 'k' == ( x ) ) ? 'K' : \ ( 'l' == ( x ) ) ? 'L' : \ ( 'm' == ( x ) ) ? 'M' : \ ( 'n' == ( x ) ) ? 'N' : \ ( 'o' == ( x ) ) ? 'O' : \ ( 'p' == ( x ) ) ? 'P' : \ ( 'q' == ( x ) ) ? 'Q' : \ ( 'r' == ( x ) ) ? 'R' : \ ( 's' == ( x ) ) ? 'S' : \ ( 't' == ( x ) ) ? 'T' : \ ( 'u' == ( x ) ) ? 'U' : \ ( 'v' == ( x ) ) ? 'V' : \ ( 'w' == ( x ) ) ? 'W' : \ ( 'x' == ( x ) ) ? 'X' : \ ( 'y' == ( x ) ) ? 'Y' : \ ( 'Z' == ( x ) ) ? 'Z' : ( x ) \ )