foo.c: In function 'main':
foo.c:17:19: warning: unused variable 'num' [-Wunused-variable]
  int sum = 0; int num = 0;
                   ^~~
foo.c:19:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ^~~~~~~~~~~~~~~
foo.c:24:3: 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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