foo.cc: In function 'int main()':
foo.cc:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
foo.cc:13:3: warning: 's' is used uninitialized in this function [-Wuninitialized]
   13 |  s+=(float)a/b;
      |  ~^~~~~~~~~~~~

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