View Compilation Error

0_0_38998354_17005.cpp:5:5: error: 'MAXN' was not declared in this scope
    5 | } p[MAXN],q[MAXN];
      |     ^~~~
0_0_38998354_17005.cpp:5:13: error: 'MAXN' was not declared in this scope
    5 | } p[MAXN],q[MAXN];
      |             ^~~~
0_0_38998354_17005.cpp: In function 'void input(point*)':
0_0_38998354_17005.cpp:14:5: error: 'scanf' was not declared in this scope
   14 |     scanf("%lf%lf",&(a->x),&(a->y));
      |     ^~~~~
0_0_38998354_17005.cpp: In function 'double getdis(point, point)':
0_0_38998354_17005.cpp:17:12: error: 'sqrt' was not declared in this scope
   17 |     return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
      |            ^~~~