检查给定的数字是偶数还是奇数
给定一个数字，检查它是偶数还是奇数。
示例:
Input: 2
Output: even
Input: 5
Output: odd
一个简单的解法就是除以 2 后求余数。
C++
// A simple C++ program to
// check for even or odd
#include <iostream>
using namespace std;
// Returns true if n is
// even, else odd
bool isEven(int n) { return (n % 2 == 0); }
// Driver code
int main()
{
int n = 101;
isEven(n) ? cout << "Even" : cout << "Odd";
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program program to
// check for even or odd
class GFG
{
// Returns true if n is even, else odd
public static boolean isEven(int n)
{
return (n % 2 == 0);
}
// Driver code
public static void main(String[] args)
{
int n = 101;
if(isEven(n) == true)
System.out.print("Even");
else
System.out.print("Odd");
}
}
// This code is contributed by rishabh_jain
Python 3
# A simple Python3 code
# to check for even or odd
# Returns true if n is even, else odd
def isEven(n):
return (n % 2 == 0)
# Driver code
n = 101
print("Even" if isEven(n) else "Odd")
# This code is contributed by "Sharad_Bhardwaj".
C
// C# program program to
// check for even or odd
using System;
class GFG
{
// Returns true if n is even, else odd
public static bool isEven(int n)
{
return (n % 2 == 0);
}
// Driver code
public static void Main()
{
int n = 101;
if(isEven(n) == true)
Console.WriteLine("Even");
else
Console.WriteLine("Odd");
}
}
// This code is contributed by vt_m
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// A simple PHP program to
// check for even or odd
// Returns true if n is
// even, else odd
function isEven($n)
{
return ($n % 2 == 0);
}
// Driver code
$n = 101;
if(isEven != true)
echo "Even";
else
echo "Odd";
// This code is contributed by Ajit
?>
java 描述语言
<script>
// A simple Javascript program to
// check for even or odd
// Returns true if n is
// even, else odd
function isEven(n) { return (n % 2 == 0); }
// Driver code
let n = 101;
isEven(n) ? document.write("Even") :document.write("Odd");
// This code is contributed by Mayank Tyagi
</script>
输出:
Odd
时间复杂度: O(1)
辅助空间: O(1) A 更好的解决方案**是使用按位运算符。我们需要检查最后一位是否为 1。如果最后一位是 1，那么数字是奇数，否则总是偶数。 说明:
input : 5 // odd
00000101
& 00000001
--------------
00000001
--------------
input : 8 //even
00001000
& 00000001
--------------
00000000
--------------
下面是这个想法的实现。
C++
// A simple C++ program to
// check for even or odd
#include <iostream>
using namespace std;
// Returns true if n is
// even, else odd
bool isEven(int n)
{
// n & 1 is 1, then
// odd, else even
return (!(n & 1));
}
// Driver code
int main()
{
int n = 101;
isEven(n)? cout << "Even" :
cout << "Odd";
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program program to
// check for even or odd
class GFG
{
// Returns true if n
// is even, else odd
public static boolean isEven(int n)
{
if((n & 1) == 0)
return true;
else
return false;
}
// Driver code
public static void main(String[] args)
{
int n = 101;
if(isEven(n) == true)
System.out.print("Even");
else
System.out.print("Odd");
}
}
// This code is contributed by rishabh_jain
Python 3
# A Python3 code program
# to check for even or odd
# Returns true if n is even, else odd
def isEven(n):
# n&1 is 1, then odd, else even
return (not(n & 1))
# Driver code
n = 101;
print("Even" if isEven(n) else "Odd")
# This code is contributed by "Sharad_Bhardwaj".
C
// C# program program to
// check for even or odd
using System;
class GFG
{
// Returns true if n
// is even, else odd
public static bool isEven(int n)
{
if((n & 1) == 0)
return true;
else
return false;
}
// Driver code
public static void Main()
{
int n = 101;
if(isEven(n) == true)
Console.WriteLine("Even");
else
Console.WriteLine("Odd");
}
}
// This code is contributed by vt_m.
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// A simple PHP program to
// check for even or odd
// Returns true if n is
// even, else odd
function isEven($n)
{
return (!($n & 1));
}
// Driver code
$n = 101;
if(isEven($n) == true)
echo "Even";
else
echo "Odd";
// This code is contributed by Smitha
?>
java 描述语言
<script>
// A simple JavaScript program to
// check for even or odd
// Returns true if n is
// even, else odd
function isEven(n)
{
// n & 1 is 1, then
// odd, else even
return (!(n & 1));
}
// Driver code
let n = 101;
isEven(n)? document.write("Even") :
document.write("Odd");
// This code is contributed by Manoj.
</script>
输出:
Odd
时间复杂度:0(1)
辅助空间:0(1)
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