DouKaku?

import std.stdio;
import std.date;

void main(string[] args){
    auto year = args[1];
    auto newYearsDay = parse("Jan 01 " ~ year ~ " 00:00:00 GMT+0000");
    if(newYearsDay == d_time_nan){
        return;
    }
    auto wdayOffset = WeekDay(newYearsDay);
    int total;
    writefln("#=Saturday, @=Sunday");
    foreach(i, n; [31, 28 + !!inLeapYear(newYearsDay), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]){
        writef(year, "/", i + 1);
        for(int j = 1; j <= n; j++, total++){
            writef(" ", ["@", "", "", "", "", "", "#"][(wdayOffset + total) % 7], j);
        }
        writefln();
    }
}