foo.c: In function 'main':
foo.c:23:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   23 |  scanf("%d",&n);
      |  ^~~~~~~~~~~~~~
foo.c:26:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   26 |   scanf("%d",&a[i]);
      |   ^~~~~~~~~~~~~~~~~
foo.c:28:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   28 |  scanf("%d",&x);//这个就是几次
      |  ^~~~~~~~~~~~~~

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