View Compilation Error

0_0_30420313_636.c:2:1: error: expected identifier or '(' before '/' token
 //#pragma GCC optimize(2)
 ^
0_0_30420313_636.c:2:3: error: stray '#' in program
 //#pragma GCC optimize(2)
   ^
0_0_30420313_636.c:4:19: fatal error: iostream: No such file or directory
 #include<iostream>
                   ^
compilation terminated.