foo.c: In function 'main':
foo.c:8:17: error: 'f1' undeclared (first use in this function); did you mean 'a1'?
  { printf("%d ",f1);
                 ^~
                 a1
foo.c:8:17: note: each undeclared identifier is reported only once for each function it appears in
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~

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