c-resources/CPlusPlus20ForProgrammers-m.../examples/ch09/fig09_23-27/Date.cpp

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// Fig. 9.24: Date.cpp
// Date class member-function definitions.
#include <array>
#include <fmt/format.h>
#include <iostream>
#include <stdexcept>
#include "Date.h" // include Date class definition
// constructor confirms proper value for month; calls
// utility function checkDay to confirm proper value for day
Date::Date(int year, int month, int day)
: m_year{year}, m_month{month}, m_day{day} {
if (m_month < 1 || m_month > monthsPerYear) { // validate the month
throw std::invalid_argument{"month must be 1-12"};
}
if (!checkDay(day)) { // validate the day
throw std::invalid_argument{
"Invalid day for current month and year"};
}
// output Date object to show when its constructor is called
std::cout << fmt::format("Date object constructor: {}\n", toString());
}
// gets string representation of a Date in the form yyyy-mm-dd
std::string Date::toString() const {
return fmt::format("{}-{:02d}-{:02d}", m_year, m_month, m_day);
}
// output Date object to show when its destructor is called
Date::~Date() {
std::cout << fmt::format("Date object destructor: {}\n", toString());
}
// utility function to confirm proper day value based on
// month and year; handles leap years, too
bool Date::checkDay(int day) const {
// we ignore element 0
static const std::array daysPerMonth{
0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
// determine whether testDay is valid for specified month
if (1 <= day && day <= daysPerMonth.at(m_month)) {
return true;
}
// February 29 check for leap year
if (m_month == 2 && day == 29 && (m_year % 400 == 0 ||
(m_year % 4 == 0 && m_year % 100 != 0))) {
return true;
}
return false; // invalid day, based on current m_month and m_year
}
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