foo.cc: In function 'int main()':
foo.cc:40:21: warning: format '%Lf' expects argument of type 'long double', but argument 2 has type 'double' [-Wformat=]
  printf("%.2Lf\n", r);
                     ^
foo.cc:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
foo.cc:31:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lf%lf%lf",x+i,y+i,s+i);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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