Here, we will help to understand about how to find out **Number of 1 Bits **solution of leet code 191 with code and algorithm.

You have to write a function that takes an unsigned integer and returns the number of ‘1’ bits it has (also known as the Hamming weight).

**Example:**

Input: n = 00000000000000000000000000011011 Output: 4 Explanation: The input binary string 00000000000000000000000000011011 has a total of four '1' bits. Input: n = 00000000000000000000000010000010 Output: 2 Explanation: The input binary string 00000000000000000000000010000010 has a total of two '1' bit. Input: n = 11111111111111111111111111111101 Output: 31 Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.

**Note**: The input must be a **binary string** of length `32`

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### Explanation:

This problem belongs to bits category where by using bitwise operator, you have to find out number of set bits in a given number.

### Algorithm 1:

- Iterate over bits of number
- If bit is 1 then increment the count variable.
- If bit is 0 then skip the increment the count.

- return count

## Number of 1 Bits code in C++

**Code 1:**

#include <iostream> using namespace std; int hammingWeight(uint32_t n) { int count = 0; while(n) { if(n & 1) { count++; } n >>= 1; } return count; } int main() { cout<<hammingWeight(10); return 0; }

**Code 2:**

#include <iostream> #include <algorithm> using namespace std; int hammingWeight(uint32_t n) { int count = 0; while (n > 0) { count += n & 1; n = n >> 1; } return count; } int main() { cout<<hammingWeight(10); return 0; }

**Output:**

Input: 10 in bit's: 1010 Output: 2

**Output:**

abc

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