bitset

Just a few hours ago, the following question came up: Variable cannot appear in a constant-expression Luckily for the OP, the answer provided did solve his problem, but I cannot reproduce the solution. I've attempted to simplify the code even more and I am now stuck with the following: #include <bitset> int main () { const size_t length_1 = static_cast<const size_t>(1.0f); std::bitset<length_1> bits_1; const size_t length_2 = static_cast<const size_t>(1.0f / 1.0f); std::bitset<length_2> bits_2; } If compiled with -pedantic , the first example is accepted by the compiler, but the one with a

So I know there is a way to convert Dec to binary using the bitset library but can you do the same for binary to decimal using the bitset library? or do you have to do it manually? bitset<8> bin_x(number); You can, but it should be a string. std::bitset<8> bits("1111"); std::cout << bits.to_ulong() << std::endl; You can convert your integer to string and then pass it to bitset c-tor. Live example 来源： https://stackoverflow.com/questions/19627521/c-binary-to-decimal

My source: #include <iostream> #include <bitset> using std::cout; using std::endl; typedef unsigned long long U64; const U64 MAX = 8000000000L; struct Bitmap { void insert(U64 N) {this->s.set(N % MAX);} bool find(U64 N) const {return this->s.test(N % MAX);} private: std::bitset<MAX> s; }; int main() { cout << "Bitmap size: " << sizeof(Bitmap) << endl; Bitmap* s = new Bitmap(); // ... } Compilation command and its output: g++ -g -std=c++11 -O4 tc002.cpp -o latest g++: internal compiler error: Killed (program cc1plus) Please submit a full bug report, with preprocessed source if appropriate. See

I would like to know what is the memory usage of BitSet in Scala.For example, if I do: var bitArray:BitSet=new BitSet(10) bitArray.add(0) bitArray.add(2) bitArray.add(4) bitArray.add(6) bitArray.add(8) How does that compare with and array containing the even numbers 0,2,4,6,8? What about writing a number in binary: var bitArray:BitSet=new BitSet(32) bitArray.add(5) bitArray.add(3) bitArray.add(2) bitArray.add(1) bitArray.add(0) How does that compare to the number 47? I'm asking here of memory usage. But as a more open question, if you know, what are the advantages/disadvantages or uses of

bitset 一般代替 bool 数组使用，常用于优化空间，因为 bitset 中一个元素只占 1 bit。 bitset 的大小在定义使就需要确定。如果想要不定长的 bitset，就需要使用 vector 。 bitset 的定义： bitset<16> bt; // 定义大小为16的bitset，每一位都是0 bitset<16> bt(string("11001")); // 定义大小为16的bitset，并用string初始化，注意高位为0，也就是 0000000000011001 bitset 可以直接使用 cin 和 cout 输入输出 bitset<16> bt; cin >> bt; cout << bt << endl; bitset 可以像数组一样访问或修改某一位置的元素，注意0表示低位。 bitset<8> bt; bt[0] = 1; // 00000001 bitset 也可以像一个数一样进行位运算：与(&)、或(|)、异或(^)、取反(~)、左移(<<)、右移(>>)。 常用函数： bitset<8> bt; bt.size(); // 返回大小 bt.count(); // 返回1的个数 bt.set(); // 全部置1 bt.set(pos); // pos位置1 bt.reset(); // 全部置0 bt.reset(pos); //

I searched around and could not find the performance time specifications for bitset::count(). Does anybody know what it is (O(n) or better) and where to find it? EDIT By STL I refer only to the Standard Template Library. I read this file (C:\cygwin\lib\gcc\i686-pc-cygwin\3.4.4\include\c++\bitset) on my computer. See these /// Returns the number of bits which are set. size_t count() const { return this->_M_do_count(); } size_t _M_do_count() const { size_t __result = 0; for (size_t __i = 0; __i < _Nw; __i++) __result += __builtin_popcountl(_M_w[__i]); return __result; } BTW, this is where _Nw is