Найти сколько дней прошло от одного даты до другой (структуры)

#include <iostream>
 
int days_from_civil(int y, unsigned m, unsigned d) 
{
    y -= m <= 2;
    const int era = (y >= 0 ? y : y-399) / 400;
    const unsigned yoe = static_cast<unsigned>(y - era * 400);      // [0, 399]
    const unsigned doy = (153*(m + (m > 2 ? -3 : 9)) + 2)/5 + d-1;  // [0, 365]
    const unsigned doe = yoe * 365 + yoe/4 - yoe/100 + doy;         // [0, 146096]
    return era * 146097 + static_cast<int>(doe) - 719468;
}
int main()
{
    std::cout << days_from_civil(2012, 4, 2) - days_from_civil(2003, 2, 2) << '\n';
    system("pause");
    return 0;
}

struct date

#include<iostream>
#include<string>
using namespace std;
struct date{
int day;
int month;
int year;
};
bool vis(int y){
return (y%4==0 && y%100!=0)|| y%400==0;
}
int EndofMonth(int m,int y){
switch(m){
case 1: case 3: case 5:
case 7:case 8: case 10: case 12: return 31;
case 4:case 6: case 9: case 11:return 30;
case 2: if(vis(y)) return 29;
else return 28;
 
}
}
 
int main(){
date one, two;
one=two;
cin>>one.day>>one.month>>one.year;
cin>>two.day>>two.month>>two.year;
cout<<;
return 0;
}