foo.c: In function 'main':
foo.c:16:17: warning: unused variable 'num' [-Wunused-variable]
  int sum=0; int num=0;
                 ^~~
foo.c:18:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~
foo.c:22:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s %d %d %c %c %d",
   ^~~~~~~~~~~~~~~~~~~~~~~~~~
      student[i].name,
      ~~~~~~~~~~~~~~~~
      &(student[i].grade),
      ~~~~~~~~~~~~~~~~~~~~
      &(student[i].gradeclass),
      ~~~~~~~~~~~~~~~~~~~~~~~~~
      &(student[i].ganbu),
      ~~~~~~~~~~~~~~~~~~~~
      &(student[i].xibu),
      ~~~~~~~~~~~~~~~~~~~
      &(student[i].paper));
      ~~~~~~~~~~~~~~~~~~~~

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