foo.cc: In function 'int main()':
foo.cc:12:25: error: 'st' was not declared in this scope; did you mean 'std'?
   12 |                         st+='n';
      |                         ^~
      |                         std
foo.cc:22:25: error: 'st' was not declared in this scope; did you mean 'std'?
   22 |                         st+='n';
      |                         ^~
      |                         std
foo.cc:25:17: error: 'st' was not declared in this scope; did you mean 'std'?
   25 |                 st+='y';
      |                 ^~
      |                 std
foo.cc:27:15: error: 'st' was not declared in this scope; did you mean 'std'?
   27 |         cout<<st;
      |               ^~
      |               std

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