计算数组中偶数和奇数元素的数量

对于给定的整数数组，计算偶数和奇数元素。

例子：

Input: 
int arr[5] = {2, 3, 4, 5, 6}
Output: 
Number of even elements = 3    
Number of odd elements = 2  

Input:
int arr[5] = {22, 32, 42, 52, 62}
Output: 
Number of even elements = 5  
Number of odd elements = 0

解决方案：
我们还可以检查一个数字是奇数还是偶数

• 通过对 1 和该数字进行 AND，如果结果为 1，则该数字为奇数，否则为偶数。
• 通过它的可被 2 整除。如果一个数不能被 2 整除，则称其为奇数，否则为偶数。
  

在这里，我们将检查一个数字是否为奇数，然后我们将增加奇数计数器，否则我们将增加偶数计数器。

下面是上述方法的实现：

C++

// CPP program to count number of even
// and odd elements in an array
#include 
using namespace std;
 
void CountingEvenOdd(int arr[], int arr_size)
{
    int even_count = 0;
    int odd_count = 0;
 
    // loop to read all the values in the array
    for (int i = 0; i < arr_size; i++) {
         
          // checking if a number is completely
        // divisible by 2
        if (arr[i] & 1 == 1)
            odd_count++;
        else
            even_count++;
    }
 
    cout << "Number of even elements = " << even_count
         << "\nNumber of odd elements = " << odd_count;
}
 
// Driver Code
int main()
{
    int arr[] = { 2, 3, 4, 5, 6 };
    int n = sizeof(arr) / sizeof(arr[0]);
       
      // Function Call
    CountingEvenOdd(arr, n);
}

Java

// JAVA program to count number of even
// and odd elements in an array
import java.io.*;
 
class GFG {
 
    static void CountingEvenOdd(int arr[], int arr_size)
    {
        int even_count = 0;
        int odd_count = 0;
 
        // loop to read all the values in
        // the array
        for (int i = 0; i < arr_size; i++) {
             
              // checking if a number is
            // completely divisible by 2
            if ((arr[i] & 1) == 1)
                odd_count++;
            else
                even_count++;
        }
 
        System.out.println("Number of even"
                           + " elements = " + even_count
                           + " Number of odd elements = "
                           + odd_count);
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        int arr[] = { 2, 3, 4, 5, 6 };
        int n = arr.length;
           
          // Function Call
        CountingEvenOdd(arr, n);
    }
}
 
// This code is Contributed by anuj_67.

Python3

# Python3 program to count number of
# even and odd elements in an array
 
 
def CountingEvenOdd(arr, arr_size):
    even_count = 0
    odd_count = 0
 
    # loop to read all the values
    # in the array
    for i in range(arr_size):
 
        # checking if a number is
        # completely divisible by 2
        if (arr[i] & 1 == 1):
            odd_count += 1
        else:
            even_count += 1
 
    print("Number of even elements = ",
          even_count)
    print("Number of odd elements = ",
          odd_count)
 
 
# Driver Code
arr = [2, 3, 4, 5, 6]
n = len(arr)
 
# Function Call
CountingEvenOdd(arr, n)
 
# This code is contributed by sahishelangia

C#

// C# program to count number of even
// and odd elements in an array
using System;
 
class GFG {
 
    static void CountingEvenOdd(int[] arr, int arr_size)
    {
        int even_count = 0;
        int odd_count = 0;
 
        // loop to read all the values in
        // the array
        for (int i = 0; i < arr_size; i++) {
             
              // checking if a number is
            // completely divisible by 2
            if ((arr[i] & 1) == 1)
                odd_count++;
            else
                even_count++;
        }
 
        Console.WriteLine("Number of even"
                          + " elements = " + even_count
                          + " Number of odd elements = "
                          + odd_count);
    }
 
    // Driver Code
    public static void Main()
    {
        int[] arr = { 2, 3, 4, 5, 6 };
        int n = arr.Length;
       
          // Function Call
        CountingEvenOdd(arr, n);
    }
}
 
// This code is Contributed by anuj_67.

Javascript

 
// Javascript program to count number of even
// and odd elements in an array
 
function CountingEvenOdd(arr, arr_size)
{
    let even_count = 0;
    let odd_count = 0;
 
    // loop to read all the values in the array
    for (let i = 0; i < arr_size; i++) {
         
        // checking if a number is completely
        // divisible by 2
        if (arr[i] & 1 == 1)
            odd_count++;
        else
            even_count++;
    }
 
    document.write("Number of even elements = " + even_count
        + "<br>" + "Number of odd elements = " + odd_count);
}
 
// Driver Code
 
    let arr = [ 2, 3, 4, 5, 6 ];
    let n = arr.length;
     
    // Function Call
    CountingEvenOdd(arr, n);
 
// This code is contributed by Mayank Tyagi
 

输出

Number of even elements = 3
Number of odd elements = 2

时间复杂度： O(n)