foo.cc: In function 'int main()':
foo.cc:5:9: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'int' [-Wformat=]
    5 | scanf("%d",a);
      |        ~^  ~
      |         |  |
      |         |  int
      |         int*
foo.cc:5:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    5 | scanf("%d",a);
      | ~~~~~^~~~~~~~
foo.cc:5:6: warning: 'a' is used uninitialized in this function [-Wuninitialized]
    5 | scanf("%d",a);
      | ~~~~~^~~~~~~~

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