foo.cc: In function 'int abv(int)':
foo.cc:19:1: warning: no return statement in function returning non-void [-Wreturn-type]
   19 | }
      | ^
foo.cc: In function 'int main()':
foo.cc:24:9: error: too many arguments to function 'int abv(int)'
   24 |  abv(x,y);
      |         ^
foo.cc:5:5: note: declared here
    5 | int abv(int n)
      |     ^~~

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