foo.c: In function 'main':
foo.c:20:13: warning: format '%lf' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
   printf("%lf\n",g);
           ~~^
           %d
foo.c:14:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d\n",&n);
  ^~~~~~~~~~~~~~~~
foo.c:18:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lf %lf %lf %lf\n",&a[i],&b[i],&c[i],&d[i]);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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