unsigned-long-long-int

问题 When I run the following code in VC++ 2013 (32-bit, no optimizations): #include <cmath> #include <iostream> #include <limits> double mulpow10(double const value, int const pow10) { static double const table[] = { 1E+000, 1E+001, 1E+002, 1E+003, 1E+004, 1E+005, 1E+006, 1E+007, 1E+008, 1E+009, 1E+010, 1E+011, 1E+012, 1E+013, 1E+014, 1E+015, 1E+016, 1E+017, 1E+018, 1E+019, }; return pow10 < 0 ? value / table[-pow10] : value * table[+pow10]; } int main(void) { double d = 9710908999.008999; int j

来源： https://stackoverflow.com/questions/5934298/how-to-convert-a-hex-string-to-an-unsigned-long

来源： https://stackoverflow.com/questions/5934298/how-to-convert-a-hex-string-to-an-unsigned-long

问题 I am on Windows 7, 64bit and NTFS. I am building a DLL that must be 32 bit. I have a very simple routine that I'd like to implement in C++. I'm reading a large file using: unsigned long p; ifstream source(file); streampos pp(p); source.seekg(pp); For files over 4GB I tried using unsigned long long but it's not working. What am I doing wrong? I'm using GNU GCC, would it be of any use trying MSVC Express 2008/2010? Update: There seems that something is wrong with my GCC. Right now I'm testing

问题 I am on Windows 7, 64bit and NTFS. I am building a DLL that must be 32 bit. I have a very simple routine that I'd like to implement in C++. I'm reading a large file using: unsigned long p; ifstream source(file); streampos pp(p); source.seekg(pp); For files over 4GB I tried using unsigned long long but it's not working. What am I doing wrong? I'm using GNU GCC, would it be of any use trying MSVC Express 2008/2010? Update: There seems that something is wrong with my GCC. Right now I'm testing

问题 I was reading this Wikipedia article, and attempting to implement a 'map' based solution in C, where a 'map' is just an int array, initialized to 0. For some reason it works up to fib(93) , then starts outputting strange numbers. If it matter's I'm specifying -std=c99 : #include <stdio.h> #include <stdlib.h> // represents a fib num typedef unsigned long long fib_t; // the default value of our 'map' const int FIB_NULL = 0; // could get from input, set here for now const int FIB_MAX = 100; //

问题 I was using unsigned long long int for some calculations but std::cout << std::setprecision(30) << 900000000000001i64+4*pow(10, 16); Gives Output: 40900000000000000 and this std::cout << std::setprecision(30) << 900000000000011i64+4*pow(10, 16); Gives Output: 40900000000000008 Now i have no idea what is happening i tried removing i64 tries printing 4*pow(10, 16) gives the correct result 40000000000000000 also tried printing 40900000000000011 directly, it prints the correct result. It works

问题 The Standard Library class template std::bitset<N> has a constructor (C++11 and onwards, unsigned long argument before C++11) constexpr bitset(unsigned long long) noexcept Contrary to many best-practice guidelines, this single-argument constructor is not marked as explicit . What is the rationale behind this? 回答1: Explicit construction The main objection against an explicit constructor is that copy-initialization from unsigned integers no longer works constexpr auto N = 64; std::bitset<N> b

问题 The Standard Library class template std::bitset<N> has a constructor (C++11 and onwards, unsigned long argument before C++11) constexpr bitset(unsigned long long) noexcept Contrary to many best-practice guidelines, this single-argument constructor is not marked as explicit . What is the rationale behind this? 回答1: Explicit construction The main objection against an explicit constructor is that copy-initialization from unsigned integers no longer works constexpr auto N = 64; std::bitset<N> b

问题 I have a problem while using the printf function to print values of type unsigned long long int I have no idea what's wrong. I'm using Dev-Cpp 4.9.9.2 and Visual Studio 2010 Professional (I know that it's not C compiler, but anyway, wanted to try) on Windows 7 Professional 64-bit. For displaying, I used %llu modifier (according to How do you printf an unsigned long long int(the format specifier for unsigned long long int)?) but I also tried I64d with no effect... Firstly, I just wanted to