方法CountSetBits會傳回在指定位欄位中設定為 1 的位數。 語法 C++複製 DWORDCountSetBits(constDWORD Field ); 參數 欄位 將位欄位指定為DWORD值。 傳回值 傳回設定為 1 的位數。 規格需求 需求值 標頭 Winutil.h (包含 Streams.h) 程式庫
我很好奇,由BitTwiddling Hacks指出,与简单的Lookup Table方法相比,该算法的性能要好得多...现在,我想,也许我的一点研究对其他人也很有趣... PS:并行计数算法大约是35在我的计算机上平均比simpel LUT解决方案快%。 这也很好地显示了与人脑兼容的解决方案与二进制机器
In order to count number of ones in an unsigned integer we will develop a C function having signature int countSetBits(unsigned int n). This function will receive an unsigned int and return the sum of ones present in the binary string. For example, if we input 17 to countSetBits, it...
Suppose we have an integer and we need to count the number of bits that are equal to one in the binary representation of .Let’s take a look at the following example for a better understanding. Given an integer , let’s count the number of set bits in it....
Counts the number of set bits in _X inline unsigned int countbits( unsigned int _X ) restrict(amp); Parameters _X Unsigned integer value Return Value Returns the number of set bits in _X Requirements Header:amp.h Namespace:Concurrency::direct3d ...
For example,SELECT BIT_COUNT (CAST (-1 as smallint))andSELECT BIT_COUNT (CAST (-1 as int))will return 16 and 32 respectively. This is intended, as the binary representation of-1can have a different number of bits set to 1 depending on the data type. ...
unsigned int v; // count the number of bits set in 32-bit value v unsigned int c; // c is the total bits set in v // Option 1: c = BitsSetTable256[v & 0xff] + BitsSetTable256[(v >> 8) & 0xff] + BitsSetTable256[(v >> 16) & 0xff] + ...
如果要计算一个整形中的位数有多少位被置位,我们的第一想法就是循环查找。现在我们可以参考:http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel unsignedintbits_counter_v4(unsignedintx) {//count bits of each 2-bit chunkx = x - ((x >>1) &0x55555555);//count bits of ea...
Number of bits that are set totrue. Example Run this code #include <bitset>#include <iostream>intmain(){std::bitset<8>b("00010010");std::cout<<"Initial value: "<<b<<'\n';// Find the first unset bitstd::size_tidx=0;while(idx<b.size()&&b.test(idx))++idx;// Continue setti...
<<" set bit\n";// Function tocountthe// number of set bits in b2intresult2 = b2.count();cout<< b2 <<" has "<< result2 <<" set bit";return0; } 输出: 0000 has 0 set bit 0010 has 1 set bit 注:本文由纯净天空筛选整理自gopaldave大神的英文原创作品bitset count() in C++ STL...