View Compilation Error

0_0_39107420_4950.cpp: In function 'int direction(int, int, int)':
0_0_39107420_4950.cpp:4:17: error: 'ar' was not declared in this scope
    4 |         return (ar[j][0]-ar[i][0])*(ar[k][1]-ar[i][1])-(ar[k][0]-ar[i][0])*(ar[j][1]-ar[i][1]);
      |                 ^~
0_0_39107420_4950.cpp: In function 'int main()':
0_0_39107420_4950.cpp:7:27: error: 'n' was not declared in this scope
    7 |         while(scanf("%d",&n)){
      |                           ^
0_0_39107420_4950.cpp:9:21: error: 'i' was not declared in this scope
    9 |                 for(i=0;i<n;i++){
      |                     ^
0_0_39107420_4950.cpp:10:37: error: expected primary-expression before ')' token
   10 |                         scanf("%d",&)
      |                                     ^