View Compilation Error

0_0_9710482_29480.cpp: In function `bool sel(int)':
0_0_9710482_29480.cpp:27: error: `AC' undeclared (first use this function)
0_0_9710482_29480.cpp:27: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_9710482_29480.cpp:27: error: expected `;' before "par"