View Compilation Error

0_0_22431007_22384.c: In function 'main':
0_0_22431007_22384.c:7:21: error: 'M_PI' undeclared (first use in this function)
         p = log10(2*M_PI*n)/2+n*log10(n/M_E);
                     ^
0_0_22431007_22384.c:7:21: note: each undeclared identifier is reported only once for each function it appears in
0_0_22431007_22384.c:7:41: error: 'M_E' undeclared (first use in this function)
         p = log10(2*M_PI*n)/2+n*log10(n/M_E);
                                         ^