foo.cc: In function 'int main()':
foo.cc:10:2: error: expected ';' before 'if'
  if(a<3.0)
  ^~
foo.cc:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&a)
  ~~~~~^~~~~~~~~

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