foo.c: In function 'main':
foo.c:6:1: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&n);
 ^~~~~~~~~~~~~~
foo.c:10:1: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&a[i]);
 ^~~~~~~~~~~~~~~~~
foo.c:13:1: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d",&k);
 ^~~~~~~~~~~~~~

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