std::function and Type Erasure

A polymorphic wrapper that can store any callable with a compatible signature.

#include <functional>
std::function<int(int)> op;
op = [](int x){ return x+10; };
op = [](int x){ return x*2; };

Notes

• Adds indirection and possible heap allocation.

• Prefer direct callables in tight loops; use std::function for flexibility.