Cookbooks
C++
Chapter 7. Dates and Times
Getting the current date

C++:
Getting the current date

How to:

C++ provides several ways to get the current date, including the C++ standard library and third-party libraries like Boost. The following examples demonstrate how to accomplish this task.

Using <chrono> (C++20 and later)

C++20 introduced more functionalities in the <chrono> library, making it straightforward to get the current date:

#include <iostream>
#include <chrono>
#include <format> // For std::format (C++20)

int main() {
    auto current_time_point = std::chrono::system_clock::now(); // Capture the current time
    auto current_time_t = std::chrono::system_clock::to_time_t(current_time_point); // Convert to time_t

    // Format the time to a readable format
    std::cout << "Current Date: " << std::format("{:%Y-%m-%d}", std::chrono::system_clock::to_time_t(current_time_point)) << std::endl;

    return 0;
}

Sample Output:

Current Date: 2023-03-15

Using <ctime>

For programmers working with older versions of C++ or those who prefer the traditional C library:

#include <iostream>
#include <ctime>

int main() {
    std::time_t t = std::time(0); // Get current time
    std::tm* now = std::localtime(&t);
    std::cout << "Current Date: " 
              << (now->tm_year + 1900) << '-' 
              << (now->tm_mon + 1) << '-'
              <<  now->tm_mday
              << std::endl;

    return 0;
}

Sample Output:

Current Date: 2023-03-15

Using Boost Date_Time

For projects that utilize the Boost libraries, the Boost Date_Time library offers an alternative method to get the current date:

#include <iostream>
#include <boost/date_time.hpp>

int main() {
    // Get the current day using Boost's Gregorian calendar
    boost::gregorian::date today = boost::gregorian::day_clock::local_day();
    std::cout << "Current Date: " << today << std::endl;

    return 0;
}

Sample Output:

Current Date: 2023-Mar-15

These examples provide a basic foundation for working with dates in C++, crucial for a wide range of applications.

Converting a date into a stringParsing a date from a string