foo.c: In function 'input':
foo.c:6:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    6 |   scanf("%d", &a[i]);
      |   ^~~~~~~~~~~~~~~~~~
foo.c: In function 'main':
foo.c:27:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   27 |  scanf("%d",&n);
      |  ^~~~~~~~~~~~~~

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