Why C++ doesn't support named parameter [closed]

Question

Previously, I worked with python. In Python I used named parameter(keyword argument) for function calls. Wikipedia page about named parameter tells that C++ doesn't support it. Why C++ doesn't support named parameter?. Does it support in future version of C++ standard?

Answer 1

Why C++ doesn't support named parameter

Because such feature has not been introduced to the standard. The feature didn't (and doesn't) exist in C either, which is what C++ was originally based on.

Does it support in future version of C++ standard?

Maybe. A proposal has been written for it. It depends on whether the proposal is voted into the standard.

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Update: The proposal has been rejected.

A fundamental problem in C++ is that the names of the parameters in function declarations aren't significant, and following program is well-defined:

void foo(int x, int y); void foo(int y, int x);   // re-declaration of the same function void foo(int, int);       // parameter names are optional void foo(int a, int b) {} // definition of the same function 

If named parameters were introduced to the language, then what parameters would be passed here?

foo(x=42, b=42); 

Named parameters require significantly different, and backwards incompatible system of parameter passing.

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You can emulate named parameters by using a single parameter of class type:

struct args {     int   a = 42;     float b = 3.14; };  void foo(args);  // usage args a{}; a.b = 10.1; foo(a); // or in C++20 foo({.b = 10.1});