std::numeri...max_exponent(3)

💖 NAME 💖

okay bestie, welcome to the std::numeri...max_exponent(3) page — the main character is std::numeric_limits::max_exponent, from the C++ Standard Library. The NAME section is literally std::numeric_limits::max_exponent — std::numeric_limits::max_exponent (yes, it repeats, that’s the bit).

✨ Synopsis ✨

static const int max_exponent;      (until C++11)
static constexpr int max_exponent;  (since C++11)

The value of std::numeric_limits<T>::max_exponent is the largest positive number n such that r^(n-1) — where r is std::numeric_limits<T>::radix — is a representable finite value of the floating-point type T. That’s the whole vibe: it’s the biggest positive n that still works out to a finite representable floating-point value, no cap.

🫶 Standard specializations 🫶

Here’s the value of std::numeric_limits<T>::max_exponent for each standard specialization:

• /* non-specialized */ — 0
• bool — 0
• char — 0
• signed char — 0
• unsigned char — 0
• wchar_t — 0
• char8_t (since C++20) — 0
• char16_t (since C++11) — 0
• char32_t (since C++11) — 0
• short — 0
• unsigned short — 0
• int — 0
• unsigned int — 0
• long — 0
• unsigned long — 0
• long long (since C++11) — 0
• unsigned long long (since C++11) — 0
• float — FLT_MAX_EXP
• double — DBL_MAX_EXP
• long double — LDBL_MAX_EXP

💅 Example 💅

This one demonstrates the relationships of max_exponent, max_exponent10, and max() for the type float. The page drops a // Run this code marker, then:

#include <iostream>
#include <limits>

int main()
{
    std::cout << "max() = " << std::numeric_limits<float>::max() << '\n'
              << "max_exponent10 = " << std::numeric_limits<float>::max_exponent10 << '\n'
              << std::hexfloat << '\n'
              << "max() = " << std::numeric_limits<float>::max() << '\n'
              << "max_exponent = " << std::numeric_limits<float>::max_exponent << '\n';
}

🍓 Output 🍓

max() = 3.40282e+38
max_exponent10 = 38

max() = 0x1.fffffep+127
max_exponent = 128

🌈 See also 🌈

• min_exponent10 — [static] the smallest negative power of ten that is a valid normalized floating-point value (public static member constant).
• min_exponent — [static] one more than the smallest negative power of the radix that is a valid normalized floating-point value (public static member constant).
• max_exponent10 — [static] the largest integer power of 10 that is a valid finite floating-point value (public static member constant).

byeee bestie, this iconic little page came from http://cppreference.com and is dated 2024.06.10 — drink water, check your exponents, mwah 💋✨