检查给定的浮点数是偶数还是奇数

给定一个浮点数，请检查它是偶数还是奇数。
我们可以通过将整数的最后一位除以2来检查整数是偶数还是奇数，但是在浮点数的情况下，我们不能仅通过将其最后一位除以2来检查给定的数字是偶数还是奇数。例如，100.70是一个奇数，但最后一位可被2整除。
例子 ：

Input : 100.7
Output : odd

Input : 98.8
Output : even

Input : 100.70
Output : odd
Trailing 0s after dot do not matter.

方法 ：

• 我们开始从其最低有效位开始遍历一个数字，直到得到一个非零数字或“。”。
• 如果数字可被2整除，则偶数为奇数
• 如果是 ‘。’比这意味着要遍历数字的小数部分，现在我们可以通过将数字除以2来确定它是0还是非零数字，以检查数字是偶数还是奇数。

下面是上述方法的实现：

C++

// CPP program to check whether given floating
// point number is even or odd
#include 
using namespace std;
 
// Function to check even or odd.
bool isEven(string s)
{
    int l = s.length();
 
    // Loop to traverse number from LSB
    bool dotSeen = false;
    for (int i = l - 1; i >= 0; i--) {
 
        // We ignore trailing 0s after dot
        if (s[i] == '0' && dotSeen == false)
            continue;
 
        // If it is '.' we will check next digit and it
        // means decimal part is traversed.
        if (s[i] == '.') {
            dotSeen = true;
            continue;
        }
 
        // If digit is divisible by 2
        // means even number.
        if ((s[i] - '0') % 2 == 0)
            return true;
 
        return false;
    }
}
 
// Driver Function
int main()
{
    string s = "100.70";
    if (isEven(s))
        cout << "Even";
    else
        cout << "Odd";
    return 0;
}

Java

// Java program to check whether given floating
// point number is even or odd
import java.util.*;
import java.lang.*;
 
public class GfG {
 
    // Function to check even or odd.
    public static boolean isEven(String s1)
    {
        int l = s1.length();
        char[] s = s1.toCharArray();
 
        // Loop to traverse number from LSB
        boolean dotSeen = false;
        for (int i = l - 1; i >= 0; i--) {
 
            // We ignore trailing 0s after dot
            if (s[i] == '0' && dotSeen == false)
                continue;
 
            // If it is '.' we will check next digit and it
            // means decimal part is traversed.
            if (s[i] == '.') {
                dotSeen = true;
                continue;
            }
 
            // If digit is divisible by 2
            // means even number.
            if ((s[i] - '0') % 2 == 0)
                return true;
 
            return false;
        }
 
        return false;
    }
 
    // Driver function
    public static void main(String argc[])
    {
        String s = "100.70";
        if (isEven(s))
            System.out.println("Even");
        else
            System.out.println("Odd");
    }
}
/* This code is contributed by Sagar Shukla */

Python3

# Python 3 program to check
# whether given floating
# point number is even or odd
 
 
# Function to check
# even or odd.
def isEven(s) :
 
    l = len(s)
  
    # Loop to traverse
    # number from LSB
    dotSeen = False
    for i in range(l - 1, -1, -1 ) :
         
        # We ignore trailing
        # 0s after dot
        if (s[i] == '0'
           and dotSeen == False) :
             continue
  
        # If it is '.' we will
        # check next digit and it
        # means decimal part is
        # traversed.
        if (s[i] == '.') :
            dotSeen = True
              continue
         
        # If digit is
        # divisible by 2
        # means even number.
        if ((int)(s[i]) % 2 == 0) :
              return True
              
        return False     
     
 
# Driver Function
s = "100.70"
if (isEven(s)) :
    print("Even")
else :
    print("Odd")
     
# This code is contributed
# by Nikita Tiwari.

C#

// C# program to check whether given floating
// point number is even or odd
using System;
 
public class GfG {
 
    // Function to check even or odd.
    public static bool isEven(string s1)
    {
        int l = s1.Length;
 
        // char[] s = s1.toCharArray();
 
        // Loop to traverse number from LSB
        bool dotSeen = false;
        for (int i = l - 1; i >= 0; i--) {
 
            // We ignore trailing 0s after dot
            if (s1[i] == '0' && dotSeen == false)
                continue;
 
            // If it is '.' we will check next
            // digit and it means decimal part
            // is traversed.
            if (s1[i] == '.') {
                dotSeen = true;
                continue;
            }
 
            // If digit is divisible by 2
            // means even number.
            if ((s1[i] - '0') % 2 == 0)
                return true;
 
            return false;
        }
 
        return false;
    }
 
    // Driver function
    public static void Main()
    {
        string s1 = "100.70";
 
        if (isEven(s1))
            Console.WriteLine("Even");
        else
            Console.WriteLine("Odd");
    }
}
 
/* This code is contributed by Vt_m */

PHP

= 0; $i--)
    {
 
        // We ignore trailing
        // 0s after dot
        if ($s[$i] == '0' && $dotSeen == false)
        continue;
 
        // If it is '.' we will
        // check next digit and it
        // means decimal part is
        // traversed.
        if ($s[$i] == '.')
        {
            $dotSeen = true;
            continue;
        }
 
        // If digit is divisible by 2
        // means even number.
        if (($s[$i] - '0') % 2 == 0)
            return true;
             
        return false;    
    }
}
 
    // Driver Code
    $s = "100.70";
    if (isEven($s))
    echo "Even";
    else
    echo "Odd";
 
// This code is contributed by aj_36
?>

Javascript

 
// Javascript program to check
// whether given floating
// point number is even or odd
 
// Function to check
// even or odd.
function isEven(s)
{
    let l = s.length;
 
    // Loop to traverse
    // number from LSB
    let dotSeen = false;
    for (let i = l - 1; i >= 0; i--)
    {
 
        // We ignore trailing
        // 0s after dot
        if (s[i] == '0' && dotSeen == false)
        continue;
 
        // If it is '.' we will
        // check next digit and it
        // means decimal part is
        // traversed.
        if (s[i] == '.')
        {
            dotSeen = true;
            continue;
        }
 
        // If digit is divisible by 2
        // means even number.
        if ((s[i] - '0') % 2 == 0)
            return true;
             
        return false;   
    }
}
 
    // Driver Code
    let s = "100.70";
    if (isEven(s))
    document.write("Even");
    else
    document.write("Odd");
 
// This code is contributed by gfgking
 

输出 ：

odd

时间复杂度： O(| s |)

辅助空间： O(1)