Is there a way in C++ to pass arguments by name like in python?

user_15114707 0
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Is there a way in C++ to pass arguments by name like in python? For example I have a function:

void foo(int a, int b = 1, int c = 3, int d = 5);

Can I somehow call it like:

foo(5 /* a */, c = 5, d = 8);

Or

foo(5, /* a */, d = 1);
parameter-passing arguments function c++
2 Answers

There are no named function parameters in C++, but you can achieve a similar effect with designated initializers from C++20.

Take all the function parameters and put them into a struct:

struct S 
{
    int a{}, b{}, c{}, d{};
};

Now modify your function to take an instance of that struct (by const& for efficiency)

void foo(S s) 
{
    std::cout << s.a << " " << s.b << " " << s.c << " " << s.d;  // for example
}

and now you can call the function like this:

foo({.a = 2, .c = 3});  // prints 2 0 3 0 
                        // b and d get default values of 0

Here's a demo

user_83728530

No
You have to pass the arguments by order, so, to specify a value for d, you must also specify one for c since it's declared before it, for example

user_94228230
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