Constrained and Unconstrained Placeholders

#include <iostream>
#include <string>
auto addLambda = [](auto fir, auto sec) {
    return fir+sec;
};
template <typename T, typename T2>
auto addTemplate(T fir,T2 sec) {
    return fir+sec;
}
int main() {
    std::cout << std::boolalpha << '\n';
    std::cout << addLambda(1, 5) << " " << addTemplate(1, 5) << '\n';
    std::cout << addLambda(true, 5) << " " << addTemplate(true, 5) << '\n';
    std::cout << addLambda(1, 5.5) << " " << addTemplate(1, 5.5) << '\n';
    const std::string fir{"ge"};
    const std::string sec{"neric"};
    std::cout << addLambda(fir, sec) << " " << addTemplate(fir, sec) << '\n';
    std::cout << '\n';
}