View Compilation Error

0_0_19317917_5507.c: In function 'main':
0_0_19317917_5507.c:5:1: error: expected expression before '/' token
 // freopen("1000.in", "r", stdin);
 ^
0_0_19317917_5507.c:6:1: error: expected expression before '/' token
 // freopen("1000.out", "w", stdout);
 ^
0_0_19317917_5507.c:12:1: error: expected expression before '/' token
 // fclose(stdin);
 ^
0_0_19317917_5507.c:13:1: error: expected expression before '/' token
 // fclose(stdout);
 ^