foo.cc:2:2: error: "1nclude" after # is not a positive integer
    2 | #1nclude<iostream>
      |  ^~~~~~~
foo.cc: In function 'int main()':
foo.cc:5:3: error: 'cout' was not declared in this scope
    5 |   cout<<"Hello World!";
      |   ^~~~
foo.cc:1:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;
foo.cc:6:3: error: 'return0' was not declared in this scope
    6 |   return0;
      |   ^~~~~~~

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