为什么在C#中我的计算比Python这么快

下面是分别用 C#和 Python 编码的一个简单过程(对于那些对此过程感到好奇的人，这是欧拉计划).

Below is a simple piece of process coded in C# and Python respectively (for those of you curious about the process, it's the solution for Problem No. 5 of Project Euler).

我的问题是，下面的 C#代码仅花费9秒进行迭代，而 Python 代码的完成则需要283秒(确切地说，在Python 3.4上是283秒.3-64位和329秒(在Python 2.7.9-32位上).

My question is, the C# code below takes only 9 seconds to iterate, while completion of Python code takes 283 seconds (to be exact, 283 seconds on Python 3.4.3 - 64 bits and 329 seconds on Python 2.7.9 - 32 bits).

到目前为止，我已经在 C#和 Python 中编码了相似的过程，并且执行时间的差异是可比的.但是这次，经过的时间之间存在极大的差异.

So far, I've coded similar processes both in C# and Python and the execution time differences were comparable. This time however, there is an extreme difference between the elapsed times.

我认为，这种差异的一部分来自python语言的灵活变量类型(我怀疑python将一部分变量转换为double)，但这仍然很难解释.

I think, some part of this difference arise from the flexible variable type of python language (I suspect, python converts some part of variables into double) but this much is still hard to explain.

我在做什么错了?

我的系统:Windows-7 64位，

My system: Windows-7 64 bits,

C#-VS Express 2012(9秒)

C# - VS Express 2012 (9 seconds)

Python 3.4.3 64位(283秒)

Python 3.4.3 64 bits (283 seconds)

Python 2.7.9 32位(329秒)

Python 2.7.9 32 bits (329 seconds)

c-sharp代码:

c-sharp code:

using System;

namespace bug_vcs {
    class Program {
        public static void Main(string[] args) {
            DateTime t0 = DateTime.Now;
            int maxNumber = 20;
            bool found = false;
            long start = maxNumber;
            while (!found) {
                found = true;
                int i = 2;
                while ((i < maxNumber + 1) && found) {
                    if (start % i != 0) {
                        found = false;
                    }
                    i++;
                }
                start++;
            }
            Console.WriteLine("{0:d}", start - 1);
            Console.WriteLine("time elapsed = {0:f} sec.", (DateTime.Now - t0).Seconds);
            Console.ReadLine();
        }
    }
}

和python代码:

from datetime import datetime

t0 = datetime.now()
max_number = 20
found = False
start = max_number
while not found:
    found = True
    i = 2
    while ((i < max_number + 1) and found):
        if (start % i) != 0:
            found = False
        i += 1
    start += 1

print("number {0:d}\n".format(start - 1))

print("time elapsed = {0:f} sec.\n".format((datetime.now() - t0).seconds))