View Compilation Error

0_0_13186209_22811.c: In function 'main':
0_0_13186209_22811.c:19:2: error: expected expression before '/' token
  //   freopen("input.txt", "r", stdin);
  ^
0_0_13186209_22811.c:20:2: error: expected expression before '/' token
  //   freopen("output.txt", "w", stdout);
  ^
0_0_13186209_22811.c:35:3: error: expected expression before '/' token
   //for (i = 0; i < n; i++) printf("%d %d\n", P[i].start, P[i].end);
   ^
0_0_13186209_22811.c:37:9: error: expected expression before '/' token
         //for (i = 0; i < n; i++) printf("%d %d\n", P[i].start, P[i].end);
         ^