blocks|key|3227721|text|一种可能是显式地跳过空格(ss+>>+std::ws)，然后使用ss.peek()来查看后面是否有#。如果是，则使用ss.get()读取并继续，否则使用ss+>>+value读取该值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3227722|如果#的位置无关紧要，您还可以在使用'#'初始化stringstream之前从行中删除所有它。|3227723|entityMap^0|D|D|W|9|1D|1|1M|8|24|B|0|2|1|I|3|O|C|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|I|$]]

One possibility would be to explicitly skip whitespace (<code>ss &gt;&gt; std::ws</code>), and then to use <code>ss.peek()</code> to find out if a <code>#</code> follows. If yes, use <code>ss.get()</code> to read it and continue, otherwise use <code>ss &gt;&gt; value</code> to read the value.

If the positions of <code>#</code> don't matter, you could also remove all <code>'#'</code> from the line before initializing the <code>stringstream</code> with it.

blocks|key|4869294|text|就我个人而言，如果您的分隔符始终是空格，而不管后面是什么，我建议您只将输入作为字符串并从那里进行解析。这样，你就可以获取字符串，看看它是数字还是#之类的东西。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4869295|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|$]]

Personally, if your separator is always going to be space regardless of what follows, I'd recommend you just take the input as string and parse from there. That way, you can take the string, see if it's a number or a # and whatnot.

blocks|key|2746543|text|也许你可以把所有的值都读成std::string，然后检查它是不是"#“(如果不是--转换成int)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2746544|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|$]]

Maybe you can read all values as std::string and then check if it's "#" or not (and if not - convert to int)

blocks|key|4957091|text|我认为您应该重新检查您的前提，即“在令牌上调用atoi()会带来很大的开销--”|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4957092|对std::cin+>>+val来说没有什么神奇之处。在引擎盖下，它最终调用(与之非常相似的)+atoi。|offset|length|style|CODE|4957093|如果你的令牌很大，创建一个std::string可能会有一些开销，但正如你所说的，绝大多数是数字(其余的是#)，所以它们应该最短。|4957094|entityMap^0|0|1|F|0|D|B|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@$D|Q|E|R|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|K|$]]

I think you should re-examine your premise that "Calling atoi() on the tokens introduces big overhead-"

There is no magic to <code>std::cin &gt;&gt; val</code>. Under the hood, it ends up calling (something very similar to) atoi.

If your tokens are huge, there might be some overhead to creating a <code>std::string</code> but as you say, the vast majority are numbers (and the rest are #'s) so they should mostly be short.

blocks|key|4869371|text|int+value;
std::ifstream+input("data");
if+(input.good())+{
++++string+line;
++++std::sstream+ss(std::stringstream::in+%7C+std::stringstream::out);
++++std::sstream+ss2(std::stringstream::in+%7C+std::stringstream::out);
++++while(getline(data,+line,+'#')+{
++++++++ss+<<+line;
++++++++while(getline(ss,+line,+'+')+{
++++++++++++ss2+<<+line;
++++++++++++ss2+>>+value
++++++++++++//process+values+...
++++++++++++ss2.str("");++
++++++++}
++++++++ss.str("");
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4869372|在这里，我们首先在第一个while循环中用标记'#‘拆分该行，然后在第二个while循环中用’‘拆分该行。|unstyled|4869373|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>int value;
std::ifstream input("data");
if (input.good()) {
 string line;
 std::sstream ss(std::stringstream::in | std::stringstream::out);
 std::sstream ss2(std::stringstream::in | std::stringstream::out);
 while(getline(data, line, '#') {
 ss &lt;&lt; line;
 while(getline(ss, line, ' ') {
 ss2 &lt;&lt; line;
 ss2 &gt;&gt; value
 //process values ...
 ss2.str(""); 
 }
 ss.str("");
 }
}
</code></pre>

In here we first split the line by the token '#' in the first while loop then in the second while loop we split the line by ' '.

blocks|key|4957150|text|通常不值得对good()进行测试|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4957151|if+(input.good())+{|code-block|syntax|javascript|4957152|除非您的下一个操作是生成错误消息或异常。如果它不好，那么所有进一步的操作都将失败。|4957153|不要对EOF进行测试。|offset|length|style|CODE|4957154|while(getline(data，line)+!=+EOF)+{|4957155|std::getline()的结果不是整数。它是对输入流的引用。输入流可以转换为布尔型对象，可以在布尔型上下文(如while、if等)中使用。所以你想做的是：|4957156|while(getline(data,+line))+{|4957157|我不确定我会不会读一行。你可以只读一个单词(因为输入是空格分隔的)。在字符串上使用>>运算符|4957158|std::string+word;
while(data+>>+word)+{++//+reads+one+space+separated+word|4957159|现在您可以测试单词，看看它是否是您的特殊字符：|4957160|if+(word[0]+==+"#")|4957161|如果不是，则将该单词转换为数字。|4957162|这就是我要做的：|4957163|//+define+a+class+that+will+read+either+value+from+a+stream
class+MyValue
{
++public:
++++bool+isSpec()+const+{return+isSpecial;}
++++int++value()++const+{return+intValue;}

++++friend+std::istream&+operator>>(std::istream&+stream,+MyValue&+data)
++++{
++++++++std::string+item;
++++++++stream+>>+item;
++++++++if+(item[0]+==+'#')+{
++++++++++++data.isSpecial+=+true;
++++++++}+else
++++++++{+++data.isSpecial+=+false;
++++++++++++data.intValue++=+atoi(&item[0]);
++++++++}
++++++++return+stream;
++++}
++private:
++++bool+isSpecial;
++++int++intValue;
};

//+Now+your+loop+becomes:
MyValue++val;
while(file+>>+val)
{
++++if+(val.isSpec())++{+/*+Special+processing+*/+}
++++else+++++++++++++++{+/*+We+have+an+integer+*/+}
}|4957164|entityMap^0|0|0|0|3|3|0|0|1L|5|1R|2|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1C|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|1D|8|@$K|1E|L|1F|M|N]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1G|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1H|8|@$K|1I|L|1J|M|N]|$K|1K|L|1L|M|N]]|9|@]|A|$]]|$1|S|3|T|5|D|7|1M|8|@]|9|@]|A|$E|F]]|$1|U|3|V|5|6|7|1N|8|@]|9|@]|A|$]]|$1|W|3|X|5|D|7|1O|8|@]|9|@]|A|$E|F]]|$1|Y|3|Z|5|6|7|1P|8|@]|9|@]|A|$]]|$1|10|3|11|5|D|7|1Q|8|@]|9|@]|A|$E|F]]|$1|12|3|13|5|6|7|1R|8|@]|9|@]|A|$]]|$1|14|3|15|5|6|7|1S|8|@]|9|@]|A|$]]|$1|16|3|17|5|D|7|1T|8|@]|9|@]|A|$E|F]]|$1|18|3|-4|5|6|7|1U|8|@]|9|@]|A|$]]]|19|$]]

Usually not worth testing against good()

<pre><code>if (input.good()) {
</code></pre>

Unless your next operation is generating an error message or exception. If it is not good all further operations will fail anyway.

Don't test against <code>EOF</code>.

while(getline(data, line) != EOF) {

The result of std::getline() is not an integer. It is a reference to the input stream. The input stream is convertible to a bool like object that can be used in bool a context (like <code>while</code> <code>if</code> etc..). So what you want to do:

<pre><code>while(getline(data, line)) {
</code></pre>

I am not sure I would read a line. You could just read a word (since the input is space separated). Using the >> operator on string

<pre><code>std::string word;
while(data &gt;&gt; word) { // reads one space separated word
</code></pre>

Now you can test the word to see if it is your special character:

<pre><code>if (word[0] == "#")
</code></pre>

If not convert the word into a number.

This is what I would do:

<pre><code>// define a class that will read either value from a stream
class MyValue
{
 public:
 bool isSpec() const {return isSpecial;}
 int value() const {return intValue;}

 friend std::istream&amp; operator&gt;&gt;(std::istream&amp; stream, MyValue&amp; data)
 {
 std::string item;
 stream &gt;&gt; item;
 if (item[0] == '#') {
 data.isSpecial = true;
 } else
 { data.isSpecial = false;
 data.intValue = atoi(&amp;item[0]);
 }
 return stream;
 }
 private:
 bool isSpecial;
 int intValue;
};

// Now your loop becomes:
MyValue val;
while(file &gt;&gt; val)
{
 if (val.isSpec()) { /* Special processing */ }
 else { /* We have an integer */ }
}
</code></pre>

I have an input stream containing integers and special meaning characters '#'. It looks as follows:
<code>... 12 18 16 # 22 24 26 15 # 17 # 32 35 33 ...</code>
The tokens are separated by space. There's no pattern for the position of '#'.

I was trying to tokenize the input stream like this:

<pre><code>int value;
std::ifstream input("data");
if (input.good()) {
 string line;
 while(getline(data, line) != EOF) {
 if (!line.empty()) {
 sstream ss(line);
 while (ss &gt;&gt; value) {
 //process value ...

 }
 }
 }
}
</code></pre>

The problem with this code is that the processing stops when the first '#' is encountered. 

The only solution I can think of is to extract each individual token into a string (not '#') and use atoi() function to convert the string to an integer. However, it's very inefficient as the majority tokens are integer. Calling atoi() on the tokens introduces big overhead.

Is there a way I can parse the individual token by its type? ie, for integers, parse it as integers while for '#', skip it. Thanks!

Tokenize stringstream based on type

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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我有一个包含整数和特殊含义字符'#‘的输入流。看起来是这样的：... 12 18 16 # 22 24 26 15 # 17 # 32 35 33 ...标记之间用空格隔开。“#”的位置没有模式。我试图像这样对输入流进行标记：int value;std::ifstream input("data");if (input...

问根据类型对字符串流进行标记
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