foo.cc: In function 'int main()':
foo.cc:16:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   16 |   scanf("%d",&n);
      |   ~~~~~^~~~~~~~~
foo.cc:19:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 |     while (scanf("%d",&x),x != 0)
      |            ~~~~~^~~~~~~~~

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