View Compilation Error

0_0_21599374_11789.cpp:1:1: error: 'num' does not name a type
 num = 0;
 ^
0_0_21599374_11789.cpp:2:1: error: expected unqualified-id before 'for'
 for(int i = 2; i <= n; i++)
 ^
0_0_21599374_11789.cpp:2:16: error: 'i' does not name a type
 for(int i = 2; i <= n; i++)
                ^
0_0_21599374_11789.cpp:2:24: error: 'i' does not name a type
 for(int i = 2; i <= n; i++)
                        ^