foo.cc: In function 'int main()':
foo.cc:9:6: warning: unused variable 'a' [-Wunused-variable]
    9 |  int a[12] ;
      |      ^
foo.cc:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |  scanf("%d %d %d",&y,&m,&d);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~

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