C++ Temporary Function Objects Pattern

A C++ pattern where you create a temporary object and immediately call its function operator in

one line. The syntax Class<Template>{constructor_args}(function_args) creates an object, uses

it, then destroys it automatically.


Simple Usage Example

.

#include <iostream>

#include <vector>

// A simple function object that adds a value to each element

template<typename T>

class AddValue {

private:

T value;

public:

AddValue(T val) : value(val) {}

void operator()(std::vector<T>& arr) {

for(auto& x : arr) {

x += value;

}

}

};

int main() {

std::vector<int> numbers = {1, 2, 3, 4, 5};

// Pattern: Class<Template>{args}(target)

AddValue<int>{10}(numbers); // Add 10 to each element

// Print result

for(int x : numbers) {

std::cout << x << " "; // Output: 11 12 13 14 15

}

return 0;

}

..

This pattern is commonly used in libraries for one-time operations like filling arrays, applying

transformations, or configuring objects without creating persistent variables.

Thank you! 🙇🏻‍♂️