/in/foo.cc: In function 'int main()':
/in/foo.cc:37:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=1;i<=k;i++)
                 ~^~~
/in/foo.cc:41:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=1;i<=k;i++)
                 ~^~~