/in/foo.cc: In function 'int findnum(std::vector<int>&)':
/in/foo.cc:25:12: error: 'sec' was not declared in this scope
  int fir=0;sec=0;
            ^~~
/in/foo.cc:27:2: error: expected ',' or ';' before 'while'
  while(sec<a.size()-1){
  ^~~~~
/in/foo.cc:25:6: warning: unused variable 'fir' [-Wunused-variable]
  int fir=0;sec=0;
      ^~~
/in/foo.cc:26:6: warning: unused variable 'num' [-Wunused-variable]
  int num=0
      ^~~
/in/foo.cc:53:1: error: expected '}' at end of input
 }
 ^
/in/foo.cc:53:1: warning: no return statement in function returning non-void [-Wreturn-type]