foo.cc: In function 'int main()':
foo.cc:11:3: error: 'maxn' was not declared in this scope; did you mean 'main'?
   11 |   maxn=max(maxn,xx)
      |   ^~~~
      |   main
foo.cc:13:8: error: 'maxn' was not declared in this scope; did you mean 'main'?
   13 |  cout<<maxn;
      |        ^~~~
      |        main
foo.cc:7:6: warning: unused variable 'sum' [-Wunused-variable]
    7 |  int sum=0;
      |      ^~~

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