cpp-templates-metaprogramming

C++ templates allow you to write generic code that the compiler instantiates at compile time for different types. Templates parameterize functions and classes over types, enabling zero-runtime overhead abstractions. Type traits and concepts add compile-time type checking to ensure safety without runtime costs.

Function templates define generic functions instantiated for each type used; class templates define parameterized classes. Template specialization lets you provide custom implementations for specific types or type combinations, overriding the generic version when needed for optimization or correctness.

SFINAE (Substitution Failure Is Not An Error) removes template candidates during overload resolution when type substitution fails. Concepts provide explicit type constraints checked at compile time, replacing complex SFINAE patterns with readable, reusable predicates for cleaner, safer generic code.

Yes. Type traits are compile-time predicates that inspect type properties—is it a pointer, integral, const-qualified—without runtime overhead. You can conditionally enable code branches or specialize templates based on type trait checks, enabling type-safe generic algorithms and containers.

Use specialization to customize behavior for specific types or patterns while keeping the same template name; use overloading for related but distinct function signatures. Specialization avoids overload resolution ambiguity and enables partial specialization for template templates and pointer types.

Templates generate no runtime overhead—instantiation happens at compile time, producing the same code as hand-written specializations. Code size may increase due to template instantiation for multiple types, but you can control this with explicit instantiation and careful design.