/in/foo.cc: In function 'int main()':
/in/foo.cc:13:13: warning: unused variable 'k' [-Wunused-variable]
     int i,j,k;
             ^
/in/foo.cc: In function 'int pd()':
/in/foo.cc:69:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(w>s.length())
        ~^~~~~~~~~~~
/in/foo.cc:71:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(w<s.length())
        ~^~~~~~~~~~~