给定数字的二进制表示
编写一个程序来打印给定数字的二进制表示。
来源:微软面试集-3
方法 1:迭代 对于任意一个数，我们可以通过与“2^i”(2 提升到 I)按位 and 运算来检查它的第 I 位是 0(OFF)还是 1(ON)。
1) Let us take number 'NUM' and we want to check whether it's 0th bit is ON or OFF
bit = 2 ^ 0 (0th bit)
if NUM & bit >= 1 means 0th bit is ON else 0th bit is OFF
2) Similarly if we want to check whether 5th bit is ON or OFF
bit = 2 ^ 5 (5th bit)
if NUM & bit >= 1 means its 5th bit is ON else 5th bit is OFF.
让我们取无符号整数(32 位)，它由 0-31 位组成。要打印无符号整数的二进制表示，从第 31 位开始，检查第 31 位是开还是关，如果是开，打印“1”，否则打印“0”。现在检查第 30 位是开还是关，如果是开打印“1”，否则打印“0”，对从 31 到 0 的所有位都这样做，最后我们将得到数字的二进制表示。
C++
// C++ Program for the binary
// representation of a given number
#include <bits/stdc++.h>
using namespace std;
void bin(long n)
{
long i;
cout << "0";
for (i = 1 << 30; i > 0; i = i / 2)
{
if((n & i) != 0)
{
cout << "1";
}
else
{
cout << "0";
}
}
}
// Driver Code
int main(void)
{
bin(7);
cout << endl;
bin(4);
}
// This code is contributed by souravghosh0416
C
#include<stdio.h>
void bin(unsigned n)
{
unsigned i;
for (i = 1 << 31; i > 0; i = i / 2)
(n & i) ? printf("1") : printf("0");
}
int main(void)
{
bin(7);
printf("\n");
bin(4);
}
Java 语言(一种计算机语言，尤用于创建网站)
public class GFG
{
static void bin(long n)
{
long i;
System.out.print("0");
for (i = 1 << 30; i > 0; i = i / 2)
{
if((n & i) != 0)
{
System.out.print("1");
}
else
{
System.out.print("0");
}
}
}
// Driver code
public static void main(String[] args)
{
bin(7);
System.out.println();
bin(4);
}
}
// This code is contributed by divyesh072019.
Python 3
def bin(n) :
i = 1 << 31
while(i > 0) :
if((n & i) != 0) :
print("1", end = "")
else :
print("0", end = "")
i = i // 2
bin(7)
print()
bin(4)
# This code is contributed by divyeshrabadiya07.
C
using System;
public class GFG{
static void bin(long n)
{
long i;
Console.Write("0");
for (i = 1 << 30; i > 0; i = i / 2)
{
if((n & i) != 0)
{
Console.Write("1");
}
else
{
Console.Write("0");
}
}
}
// Driver code
static public void Main (){
bin(7);
Console.WriteLine();
bin(4);
}
}
// This code is contributed by avanitrachhadiya2155
java 描述语言
<script>
// JavaScript Program for the binary
// representation of a given number
function bin(n)
{
let i;
document.write("0");
for (i = 1 << 30; i > 0; i = Math.floor(i/2))
{
if((n & i) != 0)
{
document.write("1");
}
else
{
document.write("0");
}
}
}
bin(7);
document.write("<br>");
bin(4);
// This code is contributed by rag2127
</script>
Output
00000000000000000000000000000111
00000000000000000000000000000100
方法二:递归 下面是递归方法打印‘NUM’的二进制表示。
step 1) if NUM > 1
a) push NUM on stack
b) recursively call function with 'NUM / 2'
step 2)
a) pop NUM from stack, divide it by 2 and print it's remainder.
C++
// C++ Program for the binary
// representation of a given number
#include <bits/stdc++.h>
using namespace std;
void bin(unsigned n)
{
/* step 1 */
if (n > 1)
bin(n / 2);
/* step 2 */
cout << n % 2;
}
// Driver Code
int main(void)
{
bin(7);
cout << endl;
bin(4);
}
// This code is contributed
// by Akanksha Rai
C
// C Program for the binary
// representation of a given number
void bin(unsigned n)
{
/* step 1 */
if (n > 1)
bin(n / 2);
/* step 2 */
printf("%d", n % 2);
}
// Driver Code
int main(void)
{
bin(7);
printf("\n");
bin(4);
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program for the binary
// representation of a given number
class GFG {
static void bin(int n)
{
/* step 1 */
if (n > 1)
bin(n / 2);
/* step 2 */
System.out.print(n % 2);
}
// Driver code
public static void main(String[] args)
{
bin(7);
System.out.println();
bin(4);
}
}
// This code is contributed
// by ChitraNayal
Python 3
# Python3 Program for the binary
# representation of a given number
def bin(n):
if n > 1:
bin(n//2)
print(n % 2, end="")
# Driver Code
if __name__ == "__main__":
bin(7)
print()
bin(4)
# This code is contributed by ANKITRAI1
C
// C# Program for the binary
// representation of a given number
using System;
class GFG {
static void bin(int n)
{
// step 1
if (n > 1)
bin(n / 2);
// step 2
Console.Write(n % 2);
}
// Driver code
static public void Main()
{
bin(7);
Console.WriteLine();
bin(4);
}
}
// This code is contributed ajit
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP Program for the binary
// representation of a given number
function bin($n)
{
/* step 1 */
if ($n > 1)
bin($n/2);
/* step 2 */
echo ($n % 2);
}
// Driver code
bin(7);
echo ("\n");
bin(4);
// This code is contributed
// by Shivi_Aggarwal
?>
java 描述语言
<script>
// Javascript program for the binary
// representation of a given number
function bin(n)
{
// Step 1
if (n > 1)
bin(parseInt(n / 2, 10));
// Step 2
document.write(n % 2);
}
// Driver code
bin(7);
document.write("</br>");
bin(4);
// This code is contributed by divyeshrabadiya07
</script>
Output
111
100
方法 3:递归使用按位运算符 将十进制数转换为其二进制表示的步骤如下:
step 1: Check n > 0
step 2: Right shift the number by 1 bit and recursive function call
step 3: Print the bits of number
C++
// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
// Function to convert decimal
// to binary number
void bin(unsigned n)
{
if (n > 1)
bin(n >> 1);
printf("%d", n & 1);
}
// Driver code
int main(void)
{
bin(131);
printf("\n");
bin(3);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java implementation of the approach
class GFG {
// Function to convert decimal
// to binary number
static void bin(Integer n)
{
if (n > 1)
bin(n >> 1);
System.out.printf("%d", n & 1);
}
// Driver code
public static void main(String[] args)
{
bin(131);
System.out.printf("\n");
bin(3);
}
}
/*This code is contributed by PrinciRaj1992*/
Python 3
# Python 3 implementation of above approach
# Function to convert decimal to
# binary number
def bin(n):
if (n > 1):
bin(n >> 1)
print(n & 1, end="")
# Driver code
bin(131)
print()
bin(3)
# This code is contributed by PrinciRaj1992
C
// C# implementation of above approach
using System;
public class GFG {
// Function to convert decimal
// to binary number
static void bin(int n)
{
if (n > 1)
bin(n >> 1);
Console.Write(n & 1);
}
// Driver code
public static void Main()
{
bin(131);
Console.WriteLine();
bin(3);
}
}
/*This code is contributed by PrinciRaj1992*/
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP implementation of the approach
// Function to convert decimal
// to binary number
function bin($n)
{
if ($n > 1)
bin($n>>1);
echo ($n & 1);
}
// Driver code
bin(131);
echo "\n";
bin(3);
// This code is contributed
// by Akanksha Rai
java 描述语言
<script>
// JavaScript implementation of the approach
// Function to convert decimal
// to binary number
function bin(n)
{
if (n > 1)
bin(n >> 1);
document.write(n & 1);
}
// Driver code
bin(131);
document.write("<br>");
bin(3);
// This code is contributed by Surbhi Tyagi.
</script>
Output
10000011
11
方法 4: 使用 C++的位集
我们可以使用 C++的位集类 来存储任意数字(正数和负数)的二进制表示。它为我们提供了灵活性，可以拥有我们想要的位数，比如我们是否想要一个 32 位的二进制表示，而不是一个 8 位的数字表示。
在这篇 gfg 文章 LINK 中可以找到完整的使用 bitset 的指南。
C++
#include <bits/stdc++.h>
using namespace std;
int main()
{
int n = 5, m = -5;
bitset<8> b(n);
bitset<8> b1(m);
cout << "Binary of 5:" << b << endl;
cout << "Binary of -5:" << b1 << endl;
return 0;
}
Output:
Binary of 5:00000101
Binary of -5:11111011
方法五:Python 内置库
Python 3
def binary(num):
return int(bin(num).split('0b')[1])
if __name__ == "__main__" :
x = 10
binary_x = binary(x)
print(binary_x)
# This code is contributed by Rishika Gupta.
Output
1010
视频教程
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