foo.c: In function 'main':
foo.c:16:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ^~~~~~~~~~~~~~
foo.c:19:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
         ^~~~~~~~~~~~~~~~~
foo.c:22:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&k);
     ^~~~~~~~~~~~~~

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