View Compilation Error

0_0_23015689_7856.cpp: In function 'void FFT(Complex*, int, int)':
0_0_23015689_7856.cpp:35:23: error: 'MAXN' was not declared in this scope
     static Complex _P[MAXN];
                       ^
0_0_23015689_7856.cpp:37:11: error: '_P' was not declared in this scope
     bulid(_P, P, n, 1, 0, cnt);
           ^
0_0_23015689_7856.cpp:42:21: error: 'PI' was not declared in this scope
         double p0 = PI / m * oper;
                     ^