title: Count Set Bits In An Integer 3
signature: pub fn count_set_bits_in_an_integer_3(n: i32) -> i32 {
test_code: use std::collections::HashMap;
  use std::collections::HashSet;
  use std::cmp::*;
  use std::collections::*;
  use std::fmt::*; 
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  pub fn validate_solution(actual: i32, expected: i32)->bool{
  return actual==expected
  }
  pub fn driver(n: i32, expected: i32)->String{
      if validate_solution(PLACEHOLDER_FN_NAME(n), expected) {
        return "PASSED".to_string();
      };
      return "FAILED".to_string();
  
  }
  
  fn main() {
      println!("TEST-0...{}", driver(
        6, 
        2
      ));
      
      println!("TEST-1...{}", driver(
        58, 
        4
      ));
      
      println!("TEST-2...{}", driver(
        90, 
        4
      ));
      
      println!("TEST-3...{}", driver(
        69, 
        3
      ));
      
      println!("TEST-4...{}", driver(
        15, 
        4
      ));
      
      println!("TEST-5...{}", driver(
        54, 
        4
      ));
      
      println!("TEST-6...{}", driver(
        60, 
        4
      ));
      
      println!("TEST-7...{}", driver(
        51, 
        4
      ));
      
      println!("TEST-8...{}", driver(
        46, 
        4
      ));
      
      println!("TEST-9...{}", driver(
        91, 
        5
      ));
      
  }
source_py: def count_set_bits_in_an_integer_3(n):
      if (n == 0):
          return 0
      else:
          return (1 + count_set_bits_in_an_integer_3((n & (n - 1))))
source_cpp: int count_set_bits_in_an_integer_3(int n) {
    if ( n == 0 ) return 0;
    else return 1 + count_set_bits_in_an_integer_3 ( n & ( n - 1 ) );
  }