/in/foo.cc: In function 'int main()':
/in/foo.cc:53:21: error: 'len1' was not declared in this scope
     Output(result1, len1);
                     ^~~~
/in/foo.cc:55:21: error: 'len2' was not declared in this scope
     Output(result2, len2);
                     ^~~~
/in/foo.cc:52:9: warning: unused variable 'b1' [-Wunused-variable]
     int b1=Merge(a1,n1,a2,n2,result1);
         ^~
/in/foo.cc:54:9: warning: unused variable 'b2' [-Wunused-variable]
     int b2=Merge(a1,n1,a3,n3,result2);
         ^~