foo.cc: In function 'int main()':
foo.cc:8:5: error: 'PolyList' was not declared in this scope
    8 |     PolyList P;
      |     ^~~~~~~~
foo.cc:12:9: error: 'P' was not declared in this scope
   12 |         P.insert(c, e);
      |         ^
foo.cc:16:18: error: 'P' was not declared in this scope
   16 |     int result = P.evaluate(x);
      |                  ^

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