std::tanh,s...f,std::tanhl(3)

🎀 std::tanh,s...f,std::tanhl(3) — C++ Standard Library manual 🎀

okay so bestie, welcome to the std::tanh,s...f,std::tanhl(3) page from the C++ Standard Library manual — yes, that's the manual name, folded in right at the top like a little name tag. We're doing hyperbolic tangent family today and it's gonna be cute. 💖

🌸 NAME 🌸

std::tanh, std::tanhf, std::tanhl — the NAME line is literally std::tanh,std::tanhf,std::tanhl - std::tanh,std::tanhf,std::tanhl, and that's the whole squad: hyperbolic tangent, C++ Standard Library style. 💅

🦋 Synopsis 🦋

Defined in header <cmath>.

float       tanh ( float num );

double      tanh ( double num );                            (until C++23)

long double tanh ( long double num );
/* floating-point-type */                                   (since C++23)
                tanh ( /* floating-point-type */ num );
(constexpr since C++26)

float       tanhf( float num );                     (1) (2) (since C++11)
                                                           (constexpr since C++26)

long double tanhl( long double num );                   (3) (since C++11)
                                                           (constexpr since C++26)

Additional overloads (since C++11)

Defined in header <cmath>.

template< class Integer >                               (A)
(constexpr since C++26)

double      tanh ( Integer num );

1-3) Computes the hyperbolic tangent of num.

The library provides overloads of std::tanh for all cv-unqualified floating-point types as the type of the parameter. (since C++23)

A) Additional overloads are provided for all integer types, which are treated as double. (since C++11)

🫶 Parameters 🫶

• num — floating-point or integer value.

💖 Return value 💖

If no errors occur, the hyperbolic tangent of num (tanh(num), or the enum / -e-num / enum / +e-num formula fragments the original page shows) is returned. ✨

If a range error occurs due to underflow, the correct result (after rounding) is returned.

💀 Error handling 💀

Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559):

• if the argument is ±0, ±0 is returned.
• if the argument is ±∞, ±1 is returned.
• if the argument is NaN, NaN is returned.

📝 Notes 📝

POSIX specifies that in case of underflow, num is returned unmodified, and if that is not supported, an implementation-defined value no greater than DBL_MIN, FLT_MIN, and LDBL_MIN is returned.

The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their argument num of integer type, std::tanh(num) has the same effect as std::tanh(static_cast<double>(num)).

🌈 Example 🌈

// Run this code

#include <cmath>
#include <iostream>
#include <random>

double get_random_between(double min, double max)
{
    std::random_device rd;
    std::mt19937 gen(rd());
    return std::uniform_real_distribution<>(min, max)(gen);
}

int main()
{
    const double x = get_random_between(-1.0, 1.0);

    std::cout << std::showpos
              << "tanh(+1) = " << std::tanh(+1) << '\n'
              << "tanh(-1) = " << std::tanh(-1) << '\n'
              << "tanh(x)*sinh(2*x)-cos(2*x) = "
              << std::tanh(x) * std::sinh(2 * x) - std::cosh(2 * x) << '\n'
              // special values:
              << "tanh(+0) = " << std::tanh(+0.0) << '\n'
              << "tanh(-0) = " << std::tanh(-0.0) << '\n';
}

🍓 Output 🍓

tanh(+1) = +0.761594
tanh(-1) = -0.761594
tanh(x)*sinh(2*x)-cos(2*x) = -1
tanh(+0) = +0
tanh(-0) = -0

👀 See also 👀

• sinh, sinhf (C++11), sinhl (C++11) — computes hyperbolic sine (sinh(x)) (function).
• cosh, coshf (C++11), coshl (C++11) — computes hyperbolic cosine (cosh(x)) (function).
• atanh (C++11), atanhf (C++11), atanhl (C++11) — computes the inverse hyperbolic tangent (artanh(x)) (function).
• tanh(std::complex) — computes hyperbolic tangent of a complex number (tanh(z)) (function template).
• tanh(std::valarray) — applies the function std::tanh to each element of valarray (function template).
• C documentation for tanh.

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Source/version/date sign-off, bestie: http://cppreference.com, 2024.06.10, and std::tanh,s...f,std::tanhl(3) — that's the footer folded into a cute little outro. Mwah 💋✨