foo.c: In function 'main':
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d\n",&n);
  ^~~~~~~~~~~~~~~~
foo.c:10:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&x[i]);
   ^~~~~~~~~~~~~~~~~
foo.c:14:7: warning: 'r' is used uninitialized in this function [-Wuninitialized]
  while(r!=0)
       ^

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