如何关闭数字中的特定位（） _字节操作

本文概述

C++
Java
Python3
C#
PHP

给定数字n和值k, 请关闭n中的第k位。请注意, k = 1表示最右边的位。
例子：

Input:n = 15, k = 1 Output: 14Input:n = 14, k = 1 Output: 14 The rightmost bit was already off, so no change.Input:n = 15, k = 2 Output: 13Input:n = 15, k = 3 Output: 11Input:n = 15, k = 4 Output: 7Input:n = 15, k> = 5 Output: 15

这个想法是使用按位< < , ＆和?运算符。使用表达式” ?(1 < < (k – 1))” , 我们得到一个数字, 其中除第k个位外, 所有位均已设置。如果我们使用n对这个表达式进行按位＆运算, 我们将得到一个数字, 除了第k个位数为0外, 该位数与n相同。
【如何关闭数字中的特定位（）】以下是上述想法的实现。
C++

#include < iostream> using namespace std; //Returns a number that has all bits same as n //except the k'th bit which is made 0 int turnOffK( int n, int k) { //k must be greater than 0 if (k < = 0) return n; //Do & of n with a number with all set bits except //the k'th bit return (n & ~(1 < < (k - 1))); }//Driver program to test above function int main() { int n = 15; int k = 4; cout < < turnOffK(n, k); return 0; }

Java

//Java program to turn off a particular bit in a number import java.io.*; class TurnOff { //Function to returns a number that has all bits same as n //except the k'th bit which is made 0 static int turnOffK( int n, int k) { //k must be greater than 0 if (k < = 0 ) return n; //Do & of n with a number with all set bits except //the k'th bit return (n & ~( 1 < < (k - 1 ))); }//Driver program public static void main (String[] args) { int n = 15 ; int k = 4 ; System.out.println(turnOffK(n, k)); } } //Contributed by Pramod Kumar

Python3

# Returns a number that # has all bits same as n # except the k'th bit # which is made 0def turnOffK(n, k):# k must be greater than 0 if (k < = 0 ): return n# Do & of n with a number # with all set bits except # the k'th bit return (n & ~( 1 < < (k - 1 )))# Driver code n = 15 k = 4 print (turnOffK(n, k))# This code is contributed # by Anant Agarwal.

//C# program to turn off a //particular bit in a number using System; class GFG {//Function to returns a number //that has all bits same as n //except the k'th bit which is //made 0 static int turnOffK( int n, int k) { //k must be greater than 0 if (k < = 0) return n; //Do & of n with a number //with all set bits except //the k'th bit return (n & ~ (1 < < (k - 1))); }//Driver Code public static void Main () { int n = 15; int k = 4; Console.Write(turnOffK(n, k)); } }//This code is contributed by Nitin Mittal.

PHP

< ?php //PHP program to turn off a //particular bit in a number//Returns a number that has //all bits same as n except //the k'th bit which is made 0 function turnOffK( $n , $k ) {//k must be greater than 0 if ( $k < = 0) return $n ; //Do & of n with a number //with all set bits except //the k'th bit return ( $n & ~(1 < < ( $k - 1))); }//Driver Code $n = 15; $k = 4; echo turnOffK( $n , $k ); //This code is contributed by nitin mittal ?>

输出如下：