foo.cc: In function 'int main()':
foo.cc:7:5: error: expected ',' or ';' before 'cout'
     cout << x+y << endl;
     ^~~~
foo.cc:9:2: error: 'system' was not declared in this scope
  system("pause");
  ^~~~~~
foo.cc:9:2: note: suggested alternative: 'sys_nerr'
  system("pause");
  ^~~~~~
  sys_nerr
foo.cc:5:6: warning: unused variable 'x' [-Wunused-variable]
  int x = 123; int y = 500
      ^
foo.cc:5:19: warning: unused variable 'y' [-Wunused-variable]
  int x = 123; int y = 500
                   ^

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