View Compilation Error

0_0_39172250_30445.cpp:23:19: error: 'acos' was not declared in this scope
   23 | const double PI = acos(-1);
      |                   ^~~~
0_0_39172250_30445.cpp: In function 'double rotating_calipers(point*, int)':
0_0_39172250_30445.cpp:88:16: error: 'fabs' was not declared in this scope; did you mean 'labs'?
   88 |         while (fabs(cross(p[i], p[i+1], p[k1])) < fabs(cross(p[i], p[i+1], p[k1+1])))
      |                ^~~~
      |                labs
0_0_39172250_30445.cpp:98:22: error: 'fabs' was not declared in this scope; did you mean 'labs'?
   98 |         double tmp = fabs(cross(p[i],p[i+1],p[k1]));
      |                      ^~~~
      |                      labs