/in/foo.cc:6:2: error: expected initializer before 'int'
  int i,s,n;
  ^~~
/in/foo.cc:7:2: error: 'cin' does not name a type
  cin>>n;
  ^~~
/in/foo.cc:8:5: error: 's' does not name a type
     s=0,s=s+i;
     ^
/in/foo.cc:9:3: error: expected unqualified-id before 'for'
   for(int i=1,i<=n,i+1);
   ^~~
/in/foo.cc:10:1: error: expected unqualified-id before '{' token
 {
 ^