/in/foo.cc: In function 'int put(int)':
/in/foo.cc:51:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
            for(i=0;i<strlen(s);i++)
                    ~^~~~~~~~~~
/in/foo.cc:67:9: warning: no return statement in function returning non-void [-Wreturn-type]
         }
         ^
/in/foo.cc: In function 'int change()':
/in/foo.cc:48:5: warning: control reaches end of non-void function [-Wreturn-type]
     }
     ^