Question

How to define an exabyte constant in C++

Answer 1

// An exabyte (binary) is:
               
// 1 EiB = 2 ^ 60 bytes = 1,152,921,504,606,846,976 bytes

#include <iostream>
#include <format>

constexpr std::size_t EXABYTE = 1ULL << 60;                 // 1 EiB
constexpr std::size_t EXABYTE_DEC = 1'000'000'000'000'000'000ULL;  // 1 EB

int main() {
    std::size_t size = EXABYTE;

    std::cout << "1 EiB = " << size << " bytes\n";
    
    // The std::format Approach (C++20)
    // The ':L' tells format to use the locale provided
    std::cout << "1 EiB = "
                  << std::format(std::locale("en_US.UTF-8"), "{:L}", size) << " bytes\n";

    return 0;
}


/* 
run:

1 EiB = 1152921504606846976 bytes
1 EiB = 1,152,921,504,606,846,976 bytes

*/

 

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