/in/foo.cc: In function 'int main()':
/in/foo.cc:9:18: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for(int i=0;i<=strlen(k)-1;++i)
      |                 ~^~~~~~~~~~~~~
/in/foo.cc:13:18: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   13 |     for(int i=0;i<=strlen(c)-1;++i)
      |                 ~^~~~~~~~~~~~~
/in/foo.cc:29:15: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   29 |         if(now>strlen(k)-1)
      |            ~~~^~~~~~~~~~~~