blocks|key|2324145|text|因为如果您在毫秒内多次调用randomize+(在当前的CPU时钟速度下很可能如此)，那么您将以相同的值播种RNG。这可以保证从RNG中产生相同的输出。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2324146|随机数发生器只能被播种一次。多次播种不会使输出产生额外的随机性，实际上(正如您所发现的)可能会使输出的随机性大大降低。|2324147|entityMap^0|D|9|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|N|8|@]|D|@]|E|$]]]|I|$]]

Because if you call <code>randomize</code> more than once in a millisecond (which is rather likely at current CPU clock speeds), you are seeding the RNG with the same value. This is guaranteed to produce the same output from the RNG.

Random-number generators are only meant to be seeded once. Seeding them multiple times does not make the output extra random, and in fact (as you found) may make it much less random.

blocks|key|2324158|text|你看到的是伪随机的效果。你用一次时间播种它，它就会产生一系列的数字。因为你很快就会拉出一系列随机数，所以你用相同的数字重新播种随机数，直到下一个毫秒。虽然毫秒看起来是很短的时间，但是考虑一下你在这段时间里所做的计算量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2324159|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

What you see is the effect of pseudo-randomness. You seed it with the time once, and it generates a sequence of numbers. Since you are pulling a series of random numbers very quickly after each other, you are re-seeding the randomizer with the same number until the next millisecond. And while a millisecond seems like a short time, consider the amount of calculations you're doing in that time.

blocks|key|1111238|text|如果调用足够快，QTime::currentTime().msec()的值就不会改变，基本上是用相同的种子重新播种qsrand，导致生成的下一个随机数与前面的随机数相同。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1111239|entityMap^0|8|R|1L|6|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

If you make the call fast enough the value of <code>QTime::currentTime().msec()</code> will not change, and you're basically re-seeding <code>qsrand</code> with the same seed, causing the next random number generated to be the same as the prior one.

blocks|key|2281787|text|如果您调用qsrand+Qt函数来初始化种子，则必须调用qrand+Qt函数来生成随机数，而不是从标准库中生成rand函数。rand函数的种子初始化是srand。很抱歉挖出来了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2281788|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you call the qsrand Qt function to initialize the seed, you must call the qrand Qt function to generate a random number, not the rand function from the standard library. the seed initialization for the rand function is srand.
Sorry for the dig up.

blocks|key|2324285|text|两个问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2324286|1正如其他人所指出的，发电机正在多次被种子化。|2324287|2这不是在给定范围内生成随机数的好方法。(事实上，这对大多数发电机来说是非常糟糕的)|2324288|假设生成器的低阶位是均匀分布的.大多数发电机的情况并非如此。在大多数发电机中，随机性发生在高阶比特中。|2324289|通过使用除法后的余数，实际上是在抛出随机性。|2324290|你应该用乘法和除法进行缩放。不使用模块化操作符。例如|2324291|my_number=+start_required+%2B(+generator_output+*+range_required)/generator_maximum；|2324292|如果generator_output为0，则generator_maximum+my_number将位于start_required、start_required+%2B+range_required中。|2324293|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|V|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|W|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|X|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|Y|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|Q|$]]

Two problems:

1 As others have pointed out, the generator is being seed multiple times.

2 This is not a very good method to generate random numbers within a given range. (In fact it's very very bad for most generators )

You are assuming that the low-order bits from the generator are uniformly distributed . This is not the case with most generators. In most generators the randomness occurs in the high order bits.

By using the remainder after divisions you are in effect throwing out the randomness.

You should scale using multiplication and division. Not using the modulo operator.
eg

my_number= start_required + ( generator_output * range_required)/generator_maximum;

if generator_output is in [0, generator_maximum]
my_number will be in [start_required , start_required + range_required]

blocks|key|1111491|text|我已经找到了相同的操作，并通过使用rand()而不是srand()来解决它。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1111492|但我用它来检查我的申请。它只是工作在冰柱，所以我不需要寻找它的更新。|1111493|但如果你要做一些游戏之王，这不是一个好办法，因为你的随机化将是一样的。|1111494|entityMap^0|H|6|Q|7|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]|$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|R|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|K|$]]

I've found the same action and solved it by using <code>rand()</code> instead the <code>srand()</code>.

But I use it for checking my application. It just working in the cicle, so I don't need to look for it updates. 

But if you going to do some king of game, it isn't a good way, because your randomizing will be the same.

blocks|key|2281860|text|现代Qt+c%2B%2B+11|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2281861|#include+<random>
#include+"QDateTime"

int+getRand(int+min,+int+max){
++++unsigned+int+ms+=+static_cast<unsigned>(QDateTime::currentMSecsSinceEpoch());
++++std::mt19937+gen(ms);
++++std::uniform_int_distribution<>+uid(min,+max);++++
++++return+uid(gen);
}|code-block|syntax|javascript|2281862|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

modern Qt c++ 11

<pre><code>#include &lt;random&gt;
#include "QDateTime"

int getRand(int min, int max){
 unsigned int ms = static_cast&lt;unsigned&gt;(QDateTime::currentMSecsSinceEpoch());
 std::mt19937 gen(ms);
 std::uniform_int_distribution&lt;&gt; uid(min, max); 
 return uid(gen);
}
</code></pre>

I'm having a strange problem here, and I can't manage to find a good explanation to it, so I thought of asking you guys :

Consider the following method :

<pre><code>int MathUtility::randomize(int Min, int Max)
{
 qsrand(QTime::currentTime().msec());

 if (Min &gt; Max)
 {
 int Temp = Min;
 Min = Max;
 Max = Temp;
 }
 return ((rand()%(Max-Min+1))+Min);
}
</code></pre>

I won't explain you gurus what this method actually does, I'll instead explain my problem :

I realised that when I call this method in a loop, sometimes, I get the same random number over and over again... For example, this snippet...

<pre><code>for(int i=0; i&lt;10; ++i)
{
 int Index = MathUtility::randomize(0, 1000);
 qDebug() &lt;&lt; Index;
}
</code></pre>

...will produce something like :

567
567
567
567...etc...

I realised too, that if I don't call qsrand everytime, but only once during my application's lifetime, it's working perfectly... 

My question : Why ?

Use of qsrand, random method that is not random

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我这里有个奇怪的问题，我找不到一个很好的解释，所以我想问你们：考虑以下方法：int MathUtility::randomize(int Min, int Max){    qsrand(QTime::currentTime().msec());    if (Min > Max)    {        int Te...

问使用非随机的qsrand随机方法
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