foo.cc: In function 'int main()':
foo.cc:11:21: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'int**' [-Wformat=]
   scanf("%d%d",&m,&n);
                ~~   ^
foo.cc:11:21: warning: format '%d' expects argument of type 'int*', but argument 3 has type 'int**' [-Wformat=]
foo.cc:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&k);
  ~~~~~^~~~~~~~~
foo.cc:11:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&m,&n);
   ~~~~~^~~~~~~~~~~~~~