How to use dollar / euro sign in code to initialize a variable?

December 21, 2021

I want to write some code that uses different types of currencies, eg

struct euro {
    int value;
};

struct dollar {
    int value;
};

Now I’d like to use the euro and dollars sign in code, something like

euro e = 3€;
dollar d = 3$;

Is this possible somehow?

>Solution :

What you need is user defined lietrals. The code below worked for me using g++ 11.1.0 but I guess that there could be some problems with non ASCII €. Maybe try using EUR suffix? For negative values see this.

#include <charconv>
#include <cstring>
#include <iostream>

using ull = unsigned long long;

struct euro
{
    ull val;
};

euro operator"" _€ (ull num)
{
    return euro {num};
}

int main()
{
    euro e = 123_€;
    std::cout << e.val << '\n';
}