foo.cc: In function 'int main()':
foo.cc:44:6: warning: unused variable 'cnt' [-Wunused-variable]
   44 |  int cnt = 0;
      |      ^~~
foo.cc:49:11: warning: 'A.IntArray::n' may be used uninitialized in this function [-Wmaybe-uninitialized]
   49 |  IntArray A(a, n);
      |           ^

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