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Advanced 20 min readModule: Module 8: Templates & Metaprogramming

Function & Class Templates (template <typename T>)

Write generic, type-agnostic algorithms that compile to highly optimized specialized machine code.

What You Will Learn in This Lesson

  • Declaring function templates (template <typename T>)
  • Class templates with multiple type parameters
  • Compile-time computation with constexpr

Introduction & Core Concept

Templates are C++'s mechanism for generic programming. Unlike Java/C# generics which use runtime type erasure or boxing, C++ templates generate specialized machine code for each type at compile time.
WHY DOES THIS MATTER IN THE REAL WORLD?

Template algorithms run at the exact same native hardware speed as hand-written type-specific assembly code with zero abstraction penalty.

Generic Maximum Template Function

cpp
cpp
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#include <iostream>
 
template <typename T>
T getMax(T a, T b) {
    return (a > b) ? a : b;
}
 
int main() {
    std::cout << "Int Max: " << getMax(10, 20) << std::endl;
    std::cout << "Double Max: " << getMax(3.14, 2.71) << std::endl;
    return 0;
}

Line-by-Line Technical Breakdown

1Template definitions must typically reside in header files so the compiler can instantiate them in translation units.

Try It Yourself (Interactive Editor)

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Intelligent Code Runner & Live Sandbox[CPP]
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Industry Best Practices & Professional Standards

  • Use constexpr functions for computations that can be evaluated at compile time.

Lesson Summary & Core Takeaways

  • C++ templates deliver zero-cost generic abstractions.