Question

How to count the number of 1 bit in a given number with C++

Answer 1

#include <iostream>

int Count1Bit(int n) {
    int count = 0;
 
    while (n > 0) {
        count += n & 1;
        n >>= 1;
    }
    return count;
}

int main(void) {
    int n = 95; // 0101 1111
         
    int count = Count1Bit(n);
         
    std::cout << "Number of 1 bit = " << count;
    
    return 0;
}




/*
run:
       
Number of 1 bit = 6
       
*/

 

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Answer 2

#include <iostream>
 
int Count1Bit(int n) {
    int count = 0;
  
    while (n) {
        n &= (n - 1);
        count++;
    }
    
    return count;
}
 
int main(void) {
    int n = 95; // 0101 1111
          
    int count = Count1Bit(n);
          
    std::cout << "Number of 1 bit = " << count;
     
    return 0;
}
 
 
 
 
/*
run:
        
Number of 1 bit = 6
        
*/

 

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