foo.cc: In function ‘int main()’:
foo.cc:6:16: error: expected ‘;’ before ‘for’
    6 |         cin>>gs
      |                ^
      |                ;
    7 |         for(i=1;i<=)
      |         ~~~     
foo.cc:7:20: error: expected primary-expression before ‘)’ token
    7 |         for(i=1;i<=)
      |                    ^