foo.cc: In function 'int main()':
foo.cc:20:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   20 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
foo.cc:22:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   22 |   scanf("%d", &a[i]); b[i] = a[i] - i;
      |   ~~~~~^~~~~~~~~~~~~

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