Getting Today's Date into variable - c++

Question

i have that c++ project. i want to get today's date to compare it with a saved date in my files. i already searched but all i found is i can output it on the console but that isn't what i want. is it possible?
#include <iostream>
#include <cmath>
#include <string>
#include <chrono>
#include <ctime>
using namespace std;
static double interset = .05;
class Account{
public:
string ID;
double Balance;
void Deposit(double bal){
Balance += bal;
}
void Withdraw(double bal){
if (bal > Balance){
cout << "Please check the entered amount" << endl;
}
else{
Balance -= bal;
}
}
void BalanceInqu(){
cout << "Your Current Balance Is\t" << Balance << endl;
}
};
class SavingAccount : public Account{
public:
void intersetRate(){
\\i want to put here a function that calculates the interest rate of an client depending on his account creation date
}
};
Edit: i want to get the date to store it into variable and compare it with other dates

Answer 1

If you have the date or time for now, you just need to subtract the start time and the transform the result into days, if that's not already the case. So this means that you don't need to get the actual date for today.
The time_since_epoch can be enough, because you just want to have the difference between 2 timestamps.

Answer 2

#include <iostream>
#include <chrono>
#include <ctime>
tm chronoTPtoTM(const std::chrono::system_clock::time_point& tp) {
time_t aux = std::chrono::system_clock::to_time_t(tp);
return *localtime(&aux);
}
int main(int argc, char** argv) {
std::chrono::system_clock::time_point t = std::chrono::system_clock::now();
tm local_time = chronoTPtoTM(t);
std::cout << "Now is "
<< local_time.tm_year+1900 << "/"
<< local_time.tm_mon+1 << "/"
<< local_time.tm_mday << " "
<< local_time.tm_hour << "h"
<< local_time.tm_min << "m"
<< local_time.tm_sec << "s"
<< std::endl;
return 0;
}
This is a simple working example of the usage of the std::chrono::system_clock::time_point. This class even has comparator operators defined so you can compare two of these easily with <, >, <=, >=, "==" and "!=".
In the example, I've included a way to convert the time_point into a human readable format.