C# null coalescing operator equivalent for c++

Question

Is there a C++ equivalent for C# null coalescing operator? I am doing too many null checks in my code. So was looking for a way to reduce the amount of null code.

Answer 1

Just want to expand @Samuel Garcia's answer by generalising the template and adding helper macros to cut down on lambda boilerplate:

#include 

namespace coalesce_impl
{
    template
    auto coalesce(LHS lhs, RHS rhs) ->
        typename std::remove_reference::type&&
    {
        auto&& initialValue = lhs();
        if (initialValue)
            return std::move(initialValue);
        else
            return std::move(rhs());
    }

    template
    auto coalesce(LHS lhs, RHS rhs, RHSs ...rhss) ->
        typename std::remove_reference::type&&
    {
        auto&& initialValue = lhs();
        if (initialValue)
            return std::move(initialValue);
        else
            return std::move(coalesce(rhs, rhss...));
    }
}

#define COALESCE(x) (::coalesce_impl::coalesce([&](){ return ( x ); }))
#define OR_ELSE     ); }, [&](){ return (

Using the macros, you can just:

int* f();
int* g();
int* h();

int* x = COALESCE( f() OR_ELSE g() OR_ELSE h() );

I hope this helps.