<numbers>

Mathematische Konstanten std::numbers::pi aus Template-Werten std::numbers::pi_v<double>:

`e`	Eulersche Zahl e = 2.71828…
`log2e`	$\log_2 e$
`log10e`	$\log_{10} e$
`pi`	$\pi$ = 3.14159…
`inv_pi`	$1/\pi$
`inv_sqrtpi`	$1/\sqrt\pi$
`ln2`	$\ln 2$
`ln10`	$\ln 10$
`sqrt2`	$\sqrt 2$
`sqrt3`	$\sqrt 3$
`inv_sqrt3`	$1/\sqrt 3$
`egamma`	Euler-Mascheroni-Konstante $\gamma$ = 0.5772…
`phi`	Goldener Schnitt $\phi = \frac{1+\sqrt{5}}{2}$ = 1.618…

Beispiel

numbers.cpp

#include <iostream>
#include <numbers>
 
int main()
{
    std::cout << "e          = " << std::numbers::e << '\n';
    std::cout << "log2e      = " << std::numbers::log2e << '\n';
    std::cout << "log10e     = " << std::numbers::log10e << '\n';
    std::cout << "pi         = " << std::numbers::pi << '\n';
    std::cout << "inv_pi     = " << std::numbers::inv_pi << '\n';
    std::cout << "inv_sqrtpi = " << std::numbers::inv_sqrtpi << '\n';
    std::cout << "ln2        = " << std::numbers::ln2 << '\n';
    std::cout << "ln10       = " << std::numbers::ln10 << '\n';
    std::cout << "sqrt2      = " << std::numbers::sqrt2 << '\n';
    std::cout << "sqrt3      = " << std::numbers::sqrt3 << '\n';
    std::cout << "inv_sqrt3  = " << std::numbers::inv_sqrt3 << '\n';
    std::cout << "egamma     = " << std::numbers::egamma << '\n';
    std::cout << "phi        = " << std::numbers::phi << '\n';
}