Floating point inspection, C++ (gcc)

Language: Layout:

#include <iostream>
#include <limits>
#include <map>
#include <utility>
#include <iomanip>
#include <cstring>

const std::map<int, std::pair<std::string, std::string>> kFloatRoundStyleDefs {
    {-1, {"std::round_indeterminate", "Rounding style cannot be determined"}},
    { 0, {"std::round_toward_zero", "Rounding toward zero"}},
    { 1, {"std::round_to_nearest", "Rounding toward nearest representable value"}},
    { 2, {"std::round_toward_infinity", "Rounding toward positive infinity"}},
    { 3, {"std::round_toward_neg_infinity", "Rounding toward negative infinity "}},
};

template <class Real>
void printInfo() {
    const auto& [rsName, rsDef] = kFloatRoundStyleDefs.at(std::numeric_limits<Real>::round_style);
    std::cout << rsName << ": " << rsDef << "\n";
    std::cout<< "Real type " << (std::numeric_limits<Real>::is_iec559 ? "fulfills" : "does NOT fulfill") << " the requirements of IEEE 754 standard\n";
    const int kSignificandBitStored = std::numeric_limits<Real>::digits - 1;
    const int kHighestBit = sizeof(Real) * std::numeric_limits<unsigned char>::digits - 1;
    const int kExponentBitCount = kHighestBit - kSignificandBitStored;
    const int kExponentBias = 1 << (kExponentBitCount - 1);
    std::cout << "Sign bit: 1 bit\n";
    std::cout << "Exponent width: " << kExponentBitCount << " bits (exponent bias = " << kExponentBias << ")\n";
    std::cout << "Significand precision: " << std::numeric_limits<Real>::digits << " bits (" << kSignificandBitStored << " bits stored)\n";
    std::cout << "\n";
}
    
template <class Uint>
void printSign(Uint bits, int fromBit, int width) {
    const bool sign = static_cast<bool>(bits & (Uint{1} << fromBit));
    std::cout << std::setw(width) << sign << ": " << "+-"[sign] << "\n";
}

template <class Uint>
void printExponent(Uint bits, int fromBit, int bitCount, int width, int exponentBias) {
    std::cout << std::setw(width) << " ";
    unsigned exponentValue = 0;
    for (Uint mask = Uint{1} << fromBit; bitCount--; mask >>= 1) {
        const bool bitValue = static_cast<bool>(bits & mask);
        exponentValue = (exponentValue << 1) | bitValue;
        std::cout << bitValue;
    }
    std::cout << ": " << "2^(" << exponentValue << "-" << exponentBias << ") = 2^" << static_cast<int>(exponentValue) - exponentBias << "\n";
}

template <class Uint>
void printSignificand(Uint bits, int fromBit, int bitCount) {
    int bc = bitCount;
    for (Uint mask = Uint{1} << fromBit; bc--; mask >>= 1)
        std::cout << static_cast<bool>(bits & mask);
    std::cout << ": 1.";
    for (Uint mask = Uint{1} << fromBit; bitCount--; mask >>= 1)
        std::cout << static_cast<bool>(bits & mask);
    std::cout << "\n";
}

template <class Real>
void printBinary(Real r) {
    const int kSignificandBitStored = std::numeric_limits<Real>::digits - 1;
    const int kHighestBit = sizeof(Real) * std::numeric_limits<unsigned char>::digits - 1;
    const int kExponentBitCount = kHighestBit - kSignificandBitStored;
    const int kExponentBias = 1 << (kExponentBitCount - 1);
    
    if (!std::numeric_limits<Real>::is_iec559) {
        std::cerr<< "Real type does NOT fulfill the requirements of IEEE 754 standard\n";
        return;
    }
    
    using Uint = std::conditional_t<sizeof(Real) == sizeof(float), uint32_t, uint64_t>;
    Uint bits;
    std::memcpy(&bits, &r, sizeof(Uint));
    
    printSign(bits, kHighestBit, kSignificandBitStored);
    printExponent(bits, kHighestBit - 1, kExponentBitCount, kSignificandBitStored - kExponentBitCount, kExponentBias);
    printSignificand(bits, kSignificandBitStored - 1, kSignificandBitStored);
    std::cout << "Value = " << std::fixed << std::setprecision(std::numeric_limits<Real>::digits10 + 5) << r << "\n\n";
}

int main() {
    std::cout << "float:\n";
    printInfo<float>();
    std::cout << "double:\n";
    printInfo<double>();
    
    printBinary(0.1f);
    printBinary(0.2f);
    printBinary(0.3f);
    printBinary(0.1);
    printBinary(0.2);
    printBinary(0.3);
}

Show compiler warnings [ + ] Compiler args [ + ] Show input
Compilation time: 0.92 sec, absolute running time: 0.16 sec, cpu time: 0 sec, memory peak: 5 Mb, absolute service time: 1,13 sec