检查第 K 位是否置位
原文:https://www . geesforgeks . org/check-what-k-th-bit-set-not/
给定一个数字 n，检查 n 的 Kth 位是否置位。
示例:
Input : n = 5, k = 1
Output : SET
5 is represented as 101 in binary and has its first bit set.
Input : n = 2, k = 3
Output : NOT SET
2 is represented as 10 in binary, all higher i.e. beyond MSB, bits are NOT SET.
方法 1(使用左移运算符) 下面是查找第 k 位值的简单步骤:
1) Left shift given number 1 by k-1 to create a number that has only set bit as k-th bit.
temp = 1 << (k-1)
2) If bitwise AND of n and temp is non-zero, then result is SET else result is NOT SET.
示例:
n = 75 and k = 4
temp = 1 << (k-1) = 1 << 3 = 8
Binary Representation of temp = 0..00001000
Binary Representation of n = 0..01001011
Since bitwise AND of n and temp is non-zero, result is SET.
C++
// CPP program to check if k-th bit
// of a given number is set or not
#include <iostream>
using namespace std;
void isKthBitSet(int n, int k)
{
if (n & (1 << (k - 1)))
cout << "SET";
else
cout << "NOT SET";
}
// Driver code
int main()
{
int n = 5, k = 1;
isKthBitSet(n, k);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to check if k-th bit
// of a given number is set or not
class Number {
public static void isKthBitSet(int n,
int k)
{
if ((n & (1 << (k - 1))) > 0)
System.out.print("SET");
else
System.out.print("NOT SET");
}
// driver code
public static void main(String[] args)
{
int n = 5, k = 1;
isKthBitSet(n, k);
}
}
// This code is contributed by rishabh_jain
Python 3
# Python3 code to check if k-th bit
# of a given number is set or not
def isKthBitSet(n, k):
if n & (1 << (k - 1)):
print( "SET")
else:
print("NOT SET")
# Driver code
n = 5
k = 1
isKthBitSet(n, k)
# This code is contributed by "Sharad_Bhardwaj".
C
// C# program to check if k-th bit
// of a given number is set or not.
using System;
class GFG {
public static void isKthBitSet(int n,
int k)
{
if ((n & (1 << (k - 1))) > 0)
Console.Write("SET");
else
Console.Write("NOT SET");
}
// Driver code
public static void Main()
{
int n = 5, k = 1;
isKthBitSet(n, k);
}
}
// This code is contributed by nitin mittal.
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to check if
// k-th bit of a given
// number is set or not
function isKthBitSet($n, $k)
{
if ($n & (1 << ($k - 1)))
echo "SET";
else
echo "NOT SET";
}
// Driver code
$n = 5; $k = 1;
isKthBitSet($n, $k);
// This code is contributed
// by akt_mit
?>
java 描述语言
<script>
// Javascript program to check if k-th bit
// of a given number is set or not.
function isKthBitSet(n, k)
{
if ((n & (1 << (k - 1))) > 0)
document.write("SET");
else
document.write("NOT SET");
}
let n = 5, k = 1;
isKthBitSet(n, k);
</script>
输出:
SET
方法 2(使用右移运算符) 如果我们将 n 右移 k-1，如果第 Kth 位设置为 else 0，则最后一位为 1。
C++
// CPP program to check if k-th bit
// of a given number is set or not using
// right shift operator.
#include <iostream>
using namespace std;
void isKthBitSet(int n, int k)
{
if ((n >> (k - 1)) & 1)
cout << "SET";
else
cout << "NOT SET";
}
// Driver code
int main()
{
int n = 5, k = 1;
isKthBitSet(n, k);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to check if
// k-th bit of a given number
// is set or not using right
// shift operator.
import java.io.*;
class GFG
{
static void isKthBitSet(int n,
int k)
{
if (((n >> (k - 1)) &
1) > 0)
System.out.println("SET");
else
System.out.println("NOT SET");
}
// Driver code
public static void main (String[] args)
{
int n = 5, k = 1;
isKthBitSet(n, k);
}
}
// This code is contributed
// by ajit
Python 3
# PHP program to check if k-th bit of
# a given number is set or not using
# right shift operator.
def isKthBitSet(n, k):
if ((n >> (k - 1)) and 1):
print("SET")
else:
print("NOT SET")
# Driver code
n, k = 5, 1
isKthBitSet(n, k)
# This code contributed by
# PrinciRaj1992
C
// C# program to check if
// k-th bit of a given number
// is set or not using right
// shift operator
using System;
class GFG
{
static void isKthBitSet(int n,
int k)
{
if (((n >> (k - 1)) &
1) > 0)
Console.WriteLine("SET");
else
Console.WriteLine("NOT SET");
}
// Driver code
static public void Main ()
{
int n = 5, k = 1;
isKthBitSet(n, k);
}
}
// This code is contributed
// by ajit
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to check
// if k-th bit of a given
// number is set or not
// using right shift operator.
function isKthBitSet($n, $k)
{
if (($n >> ($k - 1)) & 1)
echo "SET";
else
echo "NOT SET";
}
// Driver code
$n = 5; $k = 1;
isKthBitSet($n, $k);
// This code is contributed
// by akt_mit
?>
java 描述语言
<script>
// Javascript program to check if
// k-th bit of a given number
// is set or not using right
// shift operator.
function isKthBitSet(n, k)
{
if (((n >> (k - 1)) &
1) > 0)
document.write("SET");
else
document.write("NOT SET");
}
// Driver Code
let n = 5, k = 1;
isKthBitSet(n, k);
// This code is contributed by sanjoy_62.
</script>
输出:
SET
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