/in/foo.cc: In function 'int main()':
/in/foo.cc:24:12: warning: unused variable 'k' [-Wunused-variable]
  int i, j, k, i1, i2;
            ^
/in/foo.cc: In function 'int find(std::__cxx11::string)':
/in/foo.cc:15:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'std::__cxx11::string find(int)':
/in/foo.cc:20:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^