mirror of
https://github.com/TheAlgorithms/C-Plus-Plus.git
synced 2026-05-07 05:42:03 +08:00
71 lines
1.8 KiB
C++
71 lines
1.8 KiB
C++
/**
|
|
* @file
|
|
* @brief Program to Count set bits in an integer
|
|
*
|
|
* @details
|
|
* Time Complexity :- O(log n)
|
|
* Space complexity :- O(1)
|
|
* @author [Swastika Gupta](https://github.com/swastyy)
|
|
*/
|
|
|
|
#include <cassert> /// for assert
|
|
#include <iostream> /// for io operations
|
|
#include <vector> /// for std::vector
|
|
|
|
/**
|
|
* @namespace bit_manipulation
|
|
* @brief bit set counting algorithm
|
|
*/
|
|
namespace bit_manipulation {
|
|
/**
|
|
* @namespace bitCount
|
|
* @brief Functions for counting set bits in binary representation of a number
|
|
*/
|
|
namespace bitCount {
|
|
/**
|
|
* @brief The main function implements set bit count
|
|
* @param n is the number whose set bit will be counted
|
|
* @returns count , the number set bit in binary representation of n
|
|
*/
|
|
|
|
std::uint64_t countSetBits(int n) {
|
|
int count = 0; // "count" variable is used to count number of 1's in binary
|
|
// representation of the number
|
|
while (n != 0) {
|
|
count += n & 1;
|
|
n = n >> 1; // n=n/2
|
|
}
|
|
return count;
|
|
}
|
|
} // namespace bitCount
|
|
} // namespace bit_manipulation
|
|
|
|
/**
|
|
* @brief Test implementations
|
|
* @returns void
|
|
*/
|
|
static void test() {
|
|
// n = 4 return 1
|
|
assert(bit_manipulation::bitCount::countSetBits(4) == 1);
|
|
// n = 6 return 2
|
|
assert(bit_manipulation::bitCount::countSetBits(6) == 2);
|
|
// n = 13 return 3
|
|
assert(bit_manipulation::bitCount::countSetBits(13) == 3);
|
|
// n = 9 return 2
|
|
assert(bit_manipulation::bitCount::countSetBits(9) == 2);
|
|
// n = 15 return 4
|
|
assert(bit_manipulation::bitCount::countSetBits(15) == 4);
|
|
// n = 25 return 3
|
|
assert(bit_manipulation::bitCount::countSetBits(25) == 3);
|
|
std::cout << "All test cases passed" << std::endl;
|
|
}
|
|
|
|
/**
|
|
* @brief Main function
|
|
* @returns 0 on exit
|
|
*/
|
|
int main() {
|
|
test(); // execute the test
|
|
return 0;
|
|
}
|