---
title: "Template metaprogramming in C++: compile-time Fibonacci"
description: "Compute Fibonacci numbers at compile time with C++ template metaprogramming: a recursive struct template with explicit specializations as base cases."
date: 2023-04-06
last_modified_at: 2026-10-02
keywords: [C++, template metaprogramming, compile-time computation, Fibonacci, templates]
---

# Template Metaprogramming - Fibonacci

Template metaprogramming is a technique in C++ that uses templates to perform computations at compile time.

## Fibonacci Implementation

The Fibonacci sequence can be implemented using template metaprogramming:

```cpp
template<int N>
struct Fibonacci {
    static const int value = Fibonacci<N-1>::value + Fibonacci<N-2>::value;
};

// Base cases
template<>
struct Fibonacci<0> {
    static const int value = 0;
};

template<>
struct Fibonacci<1> {
    static const int value = 1;
};
```

This implementation computes Fibonacci numbers at compile time, making runtime computation unnecessary. The template specializations for `N=0` and `N=1` serve as base cases to terminate the recursion.

Using this implementation, `Fibonacci<10>::value` would give you the 10th Fibonacci number, all calculated during compilation.