По текущей дате и дню недели определить день недели с такой же датой заданного года

#include <iostream>
int main()
{
    
    using namespace std;
    
    int year2,y,year, mon, day, yyear, hund, dday;
    cout<<"Enter day, month and year: ";
        cin>>day>>mon>>year;
    cout<< "Vvedine New year";
        cin>>year2;
    cout<<"Date is: "<< day <<" "<< mon <<" " << year2 <<'\n';
     if   (year2>year)y=year2-year ;
     else   y=year-year2 ; 
            yyear=year%100;
    hund=year/100;
    dday=(((mon+1)*26/10)+day+yyear+yyear/4+hund/4-2*hund)%7;
    if (year2>year) (dday+y)%7;
    else (dday-y)%7;
        
    if(dday==0)
        cout<<"Saturday\n";
    else if(dday==1)
        cout<<"Sunday\n";
    else if(dday==2)
        cout<<"Monday\n";
    else if(dday==3)
        cout<<"Tuesday\n";
    else if(dday==4)
        cout<<"Wednseday\n";
    else if(dday==5)
        cout<<"Thursday\n";
    else if(dday==6)
        cout<<"Friday\n";
    return 0;
}