foo.cc: In function 'int main()':
foo.cc:20:20: warning: unused variable 'p' [-Wunused-variable]
   20 |     for(int i = 1, p; i <= n; ++i){
      |                    ^
foo.cc:19:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
foo.cc:21:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   21 |         scanf("%d", &num[i]);
      |         ~~~~~^~~~~~~~~~~~~~~

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