C# 二进制到十进制转换 - 公式？
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Binary to Decimal Conversion - Formula?
提问by Nicholas
I've been searching a while and haven't gotten anything too useful yet, I'm working on a subnet calculator, and well I have used the decimal to binary which I found here, though, I haven't found a good way to convert binary to decimal.
我已经搜索了一段时间，但还没有得到任何有用的东西，我正在研究一个子网计算器，而且我已经使用了我在这里找到的十进制到二进制，但是，我还没有找到一个好的方法将二进制转换为十进制。
Note: Remember its FROM binary TO decimal, anyways, im in need of the formula or something like that (meaning calculating it, not the automated one).
注意：记住它从二进制到十进制，无论如何，我需要公式或类似的东西（意思是计算它，而不是自动化的）。
What I've understood by reading some other posts that you can somehow get the result by dividing by 10, but I didn't really understand it, so if anyone could point me in the right direction, I'd be glad.
我通过阅读其他一些帖子了解到，你可以通过除以 10 得到结果，但我并不真正理解它，所以如果有人能指出我正确的方向，我会很高兴。
Any and all help is very much appreciated guys! :)
任何和所有的帮助都非常感谢伙计们！:)
采纳答案by Ethan Brown
Doing it without LINQ:
在没有 LINQ 的情况下执行此操作：
var s = "101011"; // my binary "number" as a string
var dec = 0;
for( int i=0; i<s.Length; i++ ) {
// we start with the least significant digit, and work our way to the left
if( s[s.Length-i-1] == '0' ) continue;
dec += (int)Math.Pow( 2, i );
}
A number in any base can be thought of as the sum of its digits multiplied by their place value. For example, the decimal number 3906 can be written as:
任何基数中的数字都可以被认为是其数字之和乘以其位值。例如，十进制数 3906 可以写成：
3*1000 + 9*100 + 0*10 + 6*1
The place values are simply powers of ten:
位值只是十的幂：
3*10^3 + 9*10^2 + 0*10^1 + 6*10^0
(Remember that any number taken to the power of zero is 1.)
（请记住，任何数字的零次幂都是 1。）
Binary works exactly the same way, except the base is 2, not 10. For example, the binary number 101011 can be written as:
二进制的工作方式完全相同，除了基数是 2，而不是 10。例如，二进制数 101011 可以写为：
1*2^5 + 0*2^4 + 1*2^3 + 0*2^2 + 1*2^1 + 1*2^0
I hope that gives you a better understanding of binary numbers and how to convert them.
我希望这能让您更好地理解二进制数以及如何转换它们。
On a practical note, the best solution is Matt Grande's; it's always preferable to use a library method instead of rolling your own (unless you have a very good reason to do so).
实际上，最好的解决方案是 Matt Grande 的；最好使用库方法而不是滚动自己的方法（除非您有充分的理由这样做）。
回答by Matt Grande
You can do it like this:
你可以这样做：
string bin = "10010101010101";
long l = Convert.ToInt64(bin,2);
回答by as-cii
The answer is pretty straightforward. Let's assume you have xas a binary number:
答案很简单。让我们假设你有x一个二进制数：
string x = "10010101010101";
Since we know that the general formula to calculate is, starting from right, 2^index_1 + 2^index_2 + 2^index_nwe can use LINQ to do something like (not tested):
既然我们知道计算的通用公式是，从右开始，2^index_1 + 2^index_2 + 2^index_n我们可以使用 LINQ 来做类似的事情（未测试）：
x.Reverse()
.Select((element, i) => new { Index = i, Element = char.GetNumericValue(element) })
.Where(a => a.Element != 0)
.Aggregate(0.0, (a, b) => a + (Math.Pow(2, b.Index)));
回答by L.B
11010101 = 1*2^7+ 1*2^6+ 0*2^5+ 1*2^4+ 0*2^3+ 1*2^2+ 0*2^1+ 1*2^0
11010101 = 1*2^ 7+ 1*2^ 6+ 0*2^ 5+ 1*2^ 4+ 0*2^ 3+ 1*2^ 2+ 0*2^ 1+ 1*2^ 0
.................= 128 + 64 + 0 + 16 + 0 + 4 + 0 + 1
.................= 128 + 64 + 0 + 16 + 0 + 4 + 0 + 1
回答by Hachiko0
This works fine
这工作正常
using System;
class BinaryToDecimal
{
static void Main()
{
double sum = 0;
int n = 1111111; // binary number
int strn = n.ToString().Length; //how many digits has my number
for (int i = 0; i < strn; i++)
{
int lastDigit = n % 10; // get the last digit
sum = sum + lastDigit * (Math.Pow(2, i));
n = n / 10; //remove the last digit
}
Console.WriteLine(sum);
}
}
回答by Mohammed Modi
//a is an integer array which has binary value
sum = 0;
Array.Reverse(a);
for (int j = 0; j < a.Length;j++)
{
if (a[j] == 1)
sum = sum + (Math.Pow(2, j));
}
