Sword finger offer 15 Number of 1 in binary

The finger of the sword Offer 15. Binary 1 The number of

The difficulty is simple 251
Write a function , Input is an unsigned integer （ In the form of a binary string ）, Returns the number of digits in its binary expression as ‘1’ The number of （ Also known as Hamming weight ).）.

Tips ：

• Please note that , In some languages （ Such as Java） in , There is no unsigned integer type . under these circumstances , Both input and output will be specified as signed integer types , And should not affect your implementation , Because whether integers are signed or unsigned , Its internal binary representation is the same .
• stay Java in , The compiler uses Binary complement Notation to represent signed integers . therefore , Above Example 3 in , The input represents a signed integer -3.

 Example  1：
 Input ：n = 11 ( Console input  00000000000000000000000000001011) Output ：3 explain ： Binary string of input  
00000000000000000000000000001011  in , There are three of them  '1'.

 Example  2：
 Input ：n = 128 ( Console input  00000000000000000000000010000000) Output ：1 explain ： Binary string of input  00000000000000000000000010000000  in , There is one in all for  '1'.
 Example  3：
 Input ：n = 4294967293 ( Console input  11111111111111111111111111111101, In some languages  n = -3） Output ：31 explain ： Binary string of input  11111111111111111111111111111101  in , share  31  Position as  '1'.

Tips ：

• The input must be of length 32 Of Binary string .

Code

class Solution {
    
public:
    int hammingWeight(uint32_t n) {
    
        int flag=0;
        while(n){
    
            if(n&1==1)
                flag++;
            n=n>>1;
        }
        return flag;
    }
};