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:10:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&x);
   ^~~~~~~~~~~~~~
foo.c:13:6: warning: 'a[1]' may be used uninitialized in this function [-Wmaybe-uninitialized]
  max=gcd(a[0],a[1]);
      ^~~~~~~~~~~~~~
foo.c:13:6: warning: 'a[0]' may be used uninitialized in this function [-Wmaybe-uninitialized]

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