DevAcademia lesson/C++ Basics

C++ Date and Time

Topic progressTopic 69 of 109 - 63% complete

~8 min lesson21 learning blocks4 code examples1 checks/interactions

Lesson outline

Introduction

C++ provides functionality for handling date and time through the (C API) and (C++11+) libraries. These let you retrieve the current time, format it, and perform time calculations/measurements. Prefer for type safety and precision.

Getting Current Date and Time with

The library provides simple functions for retrieving and printing the current date/time. ctime() returns a pointer to a statically-allocated, thread-unsafe buffer that includes a trailing newline.

Formatted Date and Time

Use std::localtime to break down a time_t into components and std::put_time (in ) to format it safely.

Using in Modern C++

The library offers type-safe clocks, time points, and durations. Convert to time_t for legacy formatting, or (in C++20) use chrono formatting utilities.

Measuring Execution Time

Use std::chrono and a steady clock for timing code. steady_clock is monotonic and not affected by system clock changes. Avoid relying on high_resolution_clock portability - it may alias another clock.

Best Practices

Prefer for precision, arithmetic, and type safety.
Use steady_clock for measuring durations/intervals; use system_clock for real-world timestamps.
For formatted local time, use std::put_time with std::localtime; consider thread-safe variants or time zone facilities (C++20).
Store timestamps in UTC (e.g., system_clock::time_point) and convert to local time only for display.
Be mindful of time zones, daylight saving time transitions, and localization when formatting dates.

Was this topic clear?