std::chrono::duration<Rep,Period>::operator++, std::chrono::duration<Rep,Period>::operator--
Min standard notice:
Increments or decrements the number of ticks for this duration.
# Declarations
duration& operator++();
(since C++11) (constexpr since C++17)
duration operator++( int );
(since C++11) (constexpr since C++17)
duration& operator--();
(since C++11) (constexpr since C++17)
duration operator--( int );
(since C++11) (constexpr since C++17)
# Example
#include <chrono>
#include <iostream>
int main()
{
std::chrono::hours h(1);
std::chrono::minutes m = ++h;
m--;
std::cout << m.count() << " minutes\n";
}