A small, dependency-free C++ library for working with calendar dates.

This library provides simple and safe utilities for date subtraction, date addition, and common date queries, with correct handling of leap years and month/year boundaries.

Working with dates is deceptively complex. This project was created to:

• Practice real-world C++ problem solving
• Implement robust date-handling logic
• Build a reusable utility library
• Follow professional GitHub and Visual Studio standards

• Simple and clear sDate structure
• Add days to any date
• Calculate days from the beginning of the year
• Date subtraction (days → millennia)
• Date addition (days → years)
• Day-of-week calculation
• Weekend and business-day checks
• Remaining days in week, month, and year
• Leap-year–safe logic

date-utils-cpp/
├── src/
│   ├── date_utils.h     # Date structures & declarations
│   ├── date_utils.cpp  # Date utility implementations
│   └── main.cpp        # Usage examples / testing
├── date-utils-cpp.sln
├── .gitignore
└── README.md

• Language: C++
• Standard: C++17 (recommended)
• IDE: Visual Studio
• Version Control: Git & GitHub

#include <iostream>
#include "date_utils.h"

int main() {
    sDate d{29, 2, 2024};

    decreaseDateByOneDay(d);
    increaseDateByOneDay(d);

    std::cout << dayName(calculateIndex(d.day, d.month, d.year)) << std::endl;
    std::cout << "Weekend: " << isWeekEnd(d) << std::endl;
    std::cout << "Days till end of month: " << calcEndOfMonth(d) << std::endl;
}

• decreaseDateByOneDay
• decreaseDateByXDay
• decreaseDateByOneWeek
• decreaseDateByXWeek
• decreaseDateByOneMonth
• decreaseDateByXMonths
• decreaseDateByOneYear
• decreaseDateByXYearsFaster
• decreaseDateByOneDecade
• decreaseDateByXDecadesFaster
• decreaseDateByOneCentury
• decreaseDateByOneMillennium

• increaseDateByOneDay
• increaseDateByXDay
• increaseDateByXWeek
• increaseDateByXMonths
• increaseDateByXYears

• isWeekEnd
• isBusinessDay
• isEndOfWeek
• calcEndWeekDays
• calcEndOfMonth
• calcEndOfYear
• dayName
• calculateIndex

• isSameDate
• isDate1BeforeDate2
• isDate1AfterDate2
• compareDates

• isOverlap

• calculateVacationDays
• calculateVacationEndDate

All functionality is demonstrated in main.cpp and covers:

• Leap years
• Month and year boundaries
• Date addition and subtraction
• Query correctness

• C++17 or later
• No third-party dependencies
• Works with Visual Studio, GCC, and Clang

MIT License — free to use, modify, and distribute.

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