foo.cc: In function 'void Lowercase(char*)':
foo.cc:8:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<strlen(s);i++){
               ~^~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:13:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s",Refer);
   ~~~~~^~~~~~~~~~~~

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