how to implement named parameter like property in c++

Question

I have a sorting function inside class Array and wanted to achieve something like in python sort(reverse=True). I want to show user that they can pass this parameter because right now arr.bubble_sort(true); (check the code) dose not make much sense. I don't want lambda functions any idea how to achieve this.
Any other method also works because I know named parameters are not there in c++ probably.

PS: I have overloaded it by the way.
Regards,


// inside class Array

void bubble_sort(bool rev){   //overloaded bubble_sort
        if(rev){
            int i,j;
            for(i=0; i<size-1; i++){
                for(j=0; j<size-i-1; j++){
                    if(arr[j] < arr[j+1]){
                        std::swap(arr[j], arr[j+1]);
                    }
                }
            }
        }
        else{
            int i,j;
            for(i=0; i<size-1; i++){
                for(j=0; j<size-i-1; j++){
                    if(arr[j] > arr[j+1]){
                        std::swap(arr[j], arr[j+1]);
                    }
                }
            }
        }
    }


int main()
{
    int n;
    std::cin >> n;
    Array arr(n); // parameterized constructor initializing array of size n
    arr.bubble_sort(true);
    arr.print();

   return 0;
}

No, you have not overloaded `bubble_sort`, at least not in the code you've shown. But overloading it would be an elegant solution. Or use a default value for the `rev`. — Lukas-T, Oct 25 '20 at 07:20
Some compile-time parameter + `if constexpr` can be used to avoid code duplication here. — Evg, Oct 25 '20 at 07:22
Is there any reason why you use bubblesort instead of `std::sort`? — Ted Lyngmo, Oct 25 '20 at 07:26

Marek R · Accepted Answer · 2020-10-25T07:38:07.980

2

Just provide this overloads:

void bubble_sort(std::function<bool<int, int>> cmp) {
    ...
                    if(cmp(arr[j], arr[j+1])){
                        std::swap(arr[j], arr[j+1]);
                    }
    ...
}

void bubble_sort(bool rev = false)
{
    bubble_sort(rev ? std::greater<int>{} : std::less<int>{});
}

Note that in c++ is static typed language, so overloads can be distinguish by argument type.

edited Oct 25 '20 at 07:38

answered Oct 25 '20 at 07:26

Marek R

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If compiler is not smart enough, `cmp` will be a virtual call here. – Evg Oct 25 '20 at 07:50
yes, but he is a beginner and this detail is not important from his point of view. Introducing to him a templates would be an overkill. – Marek R Oct 25 '20 at 07:59

how to implement named parameter like property in c++

1 Answers1