Python Program to Count set bits in an integer

In this article, we will learn about the solution to the problem statement given below.

Problem statement − We are given an integer n, we need to count the number of 1’s in the binary representation of the number

Now let’s observe the solution in the implementation below −

#naive approach

Example

 Live Demo

# count the bits
def count(n):
   count = 0
   while (n):
      count += n & 1
      n >>= 1
   return count
# main
n = 15
print("The number of bits :",count(n))

Output

The number of bits : 4

#recursive approach

Example

 Live Demo

# recursive way
def count( n):
   # base case
   if (n == 0):
      return 0
   else:
      # whether last bit is set or not
      return (n & 1) + count(n >> 1)
# main
n = 15
print("The number of bits :",count(n))

Output

The number of bits : 4

Conclusion

In this article, we have learned about how we can make a Python Program to Count set bits in an integer.

Pavitra

Updated on: 20-Dec-2019

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