When to Use Function Templates

Function templates are useful in situations where you have a generic algorithm or operation that can be applied to different types. Here are some scenarios where function templates are beneficial:

1. Type-independent operations: If you have a function that performs an operation that is independent of the specific types involved, you can use a function template to create a generic version of the function. Examples include mathematical operations, comparisons, or utility functions.
2. Reusable code: Function templates allow you to write code once and reuse it for different types, reducing code duplication and increasing maintainability.
3. Generic algorithms: When implementing algorithms that can work with various data types, function templates provide a way to write the algorithm once and instantiate it for specific types as needed.
4. Containers and iterators: Function templates are extensively used in the C++ Standard Library, particularly with containers and iterators. They allow you to write generic code that can work with different container types and iterate over them using a common interface.

Example:

1// Function template for finding the maximum of two values
2template <typename T>
3T max(T a, T b) {
4  return (a > b) ? a : b;
5}
6
7int main() {
8  // Instantiates max<int>(int, int)
9  int intMax = max(5, 10);
10  
11  // Instantiates max<double>(double, double)
12  double doubleMax = max(3.14, 2.71);
13  
14  // Instantiates max<std::string>(std::string, std::string)
15  std::string strMax = max("hello", "world");
16}

In this example, the max function template can be used to find the maximum of two values of any comparable type, demonstrating its versatility and reusability.