count_of_set_bits.cpp File Reference

Implementation to count sets bits in an integer. More...

#include <cassert>
#include <iostream>
#include <vector>

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Namespaces
	bit_manipulation
	for std::vector
	count_of_set_bits
	Functions for the count sets bits implementation.

Functions
std::uint64_t	bit_manipulation::count_of_set_bits::countSetBits (int n)
	The main function implements set bit count. More...
static void	test ()
	Self-test implementations. More...
int	main ()
	Main function. More...

Detailed Description

Implementation to count sets bits in an integer.

We are given an integer number. Let’s say, number. The task is to first calculate the binary digit of a number and then calculate the total set bits of a number.

Set bits in a binary number is represented by 1. Whenever we calculate the binary number of an integer value it is formed as the combination of 0’s and 1’s. So digit 1 is known as a set bit in computer terms. Time Complexity: O(log n) Space complexity: O(1)

Author

Swastika Gupta

Function Documentation

countSetBits()

std::uint64_t bit_manipulation::count_of_set_bits::countSetBits

(

int

n

)

The main function implements set bit count.

Parameters

n	is the number whose set bit will be counted

Returns

the count of the number set bit in the binary representation of 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;
}

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main()

int main

(

void

)

Main function.

Returns

0 on exit

           {
    test();  // run self-test implementations
    return 0;
}

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test()

static void test ( )

static

Self-test implementations.

Returns

void

                   {
    // n = 4 return 1
    assert(bit_manipulation::count_of_set_bits::countSetBits(4) == 1);
    // n = 6 return 2
    assert(bit_manipulation::count_of_set_bits::countSetBits(6) == 2);
    // n = 13 return 3
    assert(bit_manipulation::count_of_set_bits::countSetBits(13) == 3);
    // n = 9 return 2
    assert(bit_manipulation::count_of_set_bits::countSetBits(9) == 2);
    // n = 15 return 4
    assert(bit_manipulation::count_of_set_bits::countSetBits(15) == 4);
    // n = 25 return 3
    assert(bit_manipulation::count_of_set_bits::countSetBits(25) == 3);
    std::cout << "All test cases successfully passed!" << std::endl;
}

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