View Compilation Error

0_0_36369085_28255.c: In function 'main':
0_0_36369085_28255.c:42:2: error: expected expression before '/' token
  //freopen("a.txt", "w", stdout);
  ^
0_0_36369085_28255.c:55:5: error: expected expression before '/' token
     //printf("(%d:%d)\n", i, j);
     ^