foo.cc: In function 'int main()':
foo.cc:12:19: warning: format '%d' expects argument of type 'int', but argument 2 has type 'int*' [-Wformat=]
    printf("%d" ,&l);
                 ~~^
foo.cc:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d" ,&k);
  ~~~~~^~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。