/in/foo.cc: In function 'int main()':
/in/foo.cc:29:6: error: 'i' was not declared in this scope
  for(i=0;i<n2;i++)
      ^
/in/foo.cc:24:15: warning: unused variable 'count' [-Wunused-variable]
     int n1,n2,count=0;
               ^~~~~