C++ Numerics and Time

C++ Numerics and Time

Chrono, random, math, numbers, ratio, complex, and valarray facilities grouped for quick lookup.

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C++ Numerics and Time

Time and clocks from `<chrono>`

durations and duration literals
time_point
system_clock, steady_clock, high_resolution_clock
calendars, time zones, and date/time formatting in modern C++

Randomness from `<random>`

engines such as std::mt19937, std::mt19937_64
distributions such as uniform, normal, bernoulli, poisson, exponential
seed sequences and random-device based seeding

Math and constants

<cmath> for floating-point math and classification
<numbers> for constants such as pi and e
<ratio> for compile-time rational arithmetic

Numeric and mathematical data types

<complex> for complex arithmetic
<valarray> for element-wise numeric operations

Practical use

use steady_clock for elapsed timing and timeouts
use system_clock for user-visible timestamps
pair <random> engines with named distributions instead of ad hoc modulo logic
use <numbers> constants instead of hand-written magic values when available

Example in practice

#include <chrono>

int main() {
    using namespace std::chrono_literals;
    auto timeout = 150ms;
    auto next = std::chrono::steady_clock::now() + timeout;
    return next.time_since_epoch().count() > 0 ? 0 : 1;
}