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);
  ^~~~~~~~~~~~~~
foo.c:11:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ^~~~~~~~~~~~~~~~~
foo.c:48:20: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%d %d",b[j-2]+2,b[j-1]+2);
                   ~^~

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