What are the disadvantages of using templates?

Question

Some of the disadvantages would be

1. its syntax is complex
2. compiler generates extra code

Answer 1

The only real disadvantage is that if you make any tiny syntax error in a template (especially one used by other templates) the error messages are not gonna be helpful... expect a couple pages of almost-unusable error msgs;-). Compilers' defect are very compiler-specific, and the syntax, while ugly, is not really "complex". All in all, though -- despite the huge issue with proper error diagnostics -- templates are still the single best thing about C++, the one thing that might well tempt you to use C++ over other languages with inferior implementations of generics, such as Java...