How to write a C++ template function?

Steps to write a C++ template function: Declare template parameters enclosed in angle brackets . When called, the compiler infers parameter types. Multiple template parameters can be used. Practical case: writing a function that compares values ​​of different types.

A guide to writing C++ template functions

C++ template functions are a powerful tool that allow you to write reusable code that works with a variety of data types. Here is a step-by-step guide to writing C++ template functions:

1. Syntax

Template functions are declared using template parameters enclosed in angle brackets . The function is declared as follows:

template<typename T>
T max(T a, T b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}

<typename T> is a template parameter, which indicates that the function will apply to any data type that follows it.

2. Type inference

When calling a template function, the compiler will infer the type of the template parameter. For example, if you call:

int max_value = max(10, 20);

the compiler will infer that <T> is int, so the call looks like:

int max(int a, int b) {
  // ...
}

3. Multiple template parameters

The template function can have multiple template parameters. For example, you can write a max function with two template parameters:

template<typename T, typename U>
std::pair<T, U> max(T a, U b) {
  if (a > b) {
    return {a, b};
  } else {
    return {b, a};
  }
}

Practical example: Comparing values ​​of different types

Consider the following scenario : You have a function that compares values ​​of different types, such as integers and floats. To do this, you can write a template function:

template<typename T>
bool is_greater(T a, T b) {
  return a > b;
}

This function works for any comparable data type. You can call it like this:

bool is_greater_int = is_greater(10, 20);  // true
bool is_greater_float = is_greater(1.5f, 2.5f);  // true

Conclusion

By following these steps, you can easily write C++ template functions. This will enable you to write code that is reusable and versatile, regardless of the data type.

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