foo.c: In function 'main':
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~
foo.c:15:7: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(i--;i>=0;i--)
      ~^~

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