foo.cc: In function 'int main(int, char**)':
foo.cc:15:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<strlen(str);i++){
          ~^~~~~~~~~~~~
foo.cc:11:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%c",&temp);
   ~~~~~^~~~~~~~~~~~

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