Variadic template
A variadic template is a C++ template that uses a parameter pack to accept a variable number of template arguments.
Learn C++ by Example
A variadic template is a template containing at least one parameter pack and therefore capable of accepting a variable number of template arguments.
- How it is used
- Deploys variable-arity functions, frequency counting, and grouped lambda visitors for variants.
- How deep it goes
- Explains declarations, expansions, folds, constraints, and selected overload behavior, but defers broader template internals.
- Examples
- Uses summation, frequency maps for slot-machine reels, and an Overload visitor combining lambdas.
- What you can do after
- Build variable-arity functions, expand packs into expressions or lists, and compose callable visitors for variants.
100 C++ Mistakes and How to Avoid Them
A variadic template is a C++ template that accepts a variable number of template arguments or function arguments.
- How it is used
- Handles variable numbers of template or function arguments for more generic and reusable code.
- How deep it goes
- Explains base and recursive cases, compiler expansion, and a C++17 fold-expression alternative.
- Examples
- Contrasts summing values from a vector with direct calls accepting two, three, or four arguments.
- What you can do after
- Build variable-length sum functions using a base case, recursive parameter pack, or C++17 fold expression.
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Related concepts
- templatekind of · A C++ template is a parameterized declaration or definition from which the compiler generates specialized code or types for specified arguments.
- parameter packhas part · A parameter pack is a C++ template or function parameter construct representing zero or more arguments, potentially of varying types.
- recursionuses · Recursion is a computational technique in which a definition or procedure refers to or invokes the same definition or procedure, directly or indirectly.
- fold expressionalternative to · A fold expression is a C++ expression that applies a binary operator across the elements of a parameter pack.
- frequencyuses · Frequency is the count or rate at which an item, event, outcome, or periodic cycle occurs within a specified collection or interval.
- variadic argumentsimplements · A variadic function or parameter accepts a variable number of arguments, often collecting the supplied values into a sequence of a specified type.
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