foo.cc: In function 'int main()':
foo.cc:16:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%s", s);
         ~~~~~^~~~~~~~~
foo.cc:28:24: warning: 'now' may be used uninitialized in this function [-Wmaybe-uninitialized]
             rope.insert(now, ch);
             ~~~~~~~~~~~^~~~~~~~~

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