使用stringstream进行类型转换的奇怪问题 [英] Strange problem of typecasting with stringstream
问题描述
我试图用stringstream将一些字符串转换成整数，然后
这个奇怪的问题加速了。
这是我的测试代码：
stringstream conv;
string from;
int to;
from =" 1" ;;
conv<<来自;
conv> to;
from =" 2";
conv<<来自;
conv> to;
第一次演出工作正常，但第二次演出没有奏效
all。
conv.str（）返回1在''from =" 2"之后; conv<<来自;''已执行。
然后我明确更改了conv的缓冲区，如下所示：
conv.str（" 1"）;
conv> to;
conv.str（" 2"）;
conv> to;
尽管如此，第一次演出工作完美，第二次演出失败了，= =
1.
我想知道我'我非常误解了一些事情，对不起，如果我是
问明显的话。
I was trying to cast some strings to integers with stringstream, then
this strange problem poped up.
Here is my test code:
stringstream conv;
string from;
int to;
from = "1";
conv << from;
conv >to;
from = "2";
conv << from;
conv >to;
The first casting worked fine, but the second casting didn''t work at
all.
conv.str() returned "1" after ''from = "2"; conv << from;'' was executed.
Then I explicitly changed the buffer of conv, like this:
conv.str("1");
conv >to;
conv.str("2");
conv >to;
Still, the first casting worked perfectly, the second one failed, to ==
1.
I''m wondering I''ve terribly misunderstanding something, sorry if I''m
asking the obvious.
推荐答案
< ; vi ****** @ gmail.com写信息
新闻：11 ********************* @ c28g2000cwb.googlegro ups.com ...
<vi******@gmail.comwrote in message
news:11*********************@c28g2000cwb.googlegro ups.com...
>我试图用stringstream将一些字符串转换成整数，然后
这个奇怪的问题加速了。
这是我的测试代码：
stringstream conv;
string from;
int to;
from =" 1";
con v<<来自;
conv> to;
from =" 2";
conv<<来自;
conv> to;
第一次演出工作正常，但第二次演出没有奏效
all。
conv.str（）返回1在''from =" 2"之后; conv<<来自;''已执行。
然后我明确更改了conv的缓冲区，如下所示：
conv.str（" 1"）;
conv> to;
conv.str（" 2"）;
conv> to;
尽管如此，第一次演出工作完美，第二次演出失败了，= =
1.
我想知道我'非常误解了一些事情，对不起，如果我是
问明显的事情。
>I was trying to cast some strings to integers with stringstream, then
this strange problem poped up.
Here is my test code:
stringstream conv;
string from;
int to;
from = "1";
conv << from;
conv >to;
from = "2";
conv << from;
conv >to;
The first casting worked fine, but the second casting didn''t work at
all.
conv.str() returned "1" after ''from = "2"; conv << from;'' was executed.
Then I explicitly changed the buffer of conv, like this:
conv.str("1");
conv >to;
conv.str("2");
conv >to;
Still, the first casting worked perfectly, the second one failed, to ==
1.
I''m wondering I''ve terribly misunderstanding something, sorry if I''m
asking the obvious.
我怀疑字符串流是否具有12。而不是1 2而不是1 2。或者
soemthing。我会尝试以下直到我发现什么有效。
from =" 1";
conv<< from;
conv> to;
from =" 2" ;;
conv<<来自;
conv> to;
如果没有工作，请查看
from =" ; 1 2" ;;
conv<<来自;
conv> to;
conv> to;
给你。
你可能需要在两者之间重置字符串流，但我从来没有那个
问题。
I"m suspecting that the stringstream is having "12" instead of "1 2" or
soemthing. I would try the following til I found what worked.
from = "1";
conv << from;
conv >to;
from = " 2";
conv << from;
conv >to;
if that didnt'' work see what
from = "1 2";
conv << from;
conv >to;
conv >to;
gives you.
You may need to reset the stringstream in between, but I''ve never had that
problem.
vi ****** @ gmail.com 写道：
我试图用stringstream将一些字符串转换为整数，然后
这个奇怪的问题加速了。
这是我的测试代码：
stringstream conv;
string from;
int to;
from =" 1";
conv<<来自;
conv> to;
I was trying to cast some strings to integers with stringstream, then
this strange problem poped up.
Here is my test code:
stringstream conv;
string from;
int to;
from = "1";
conv << from;
conv >to;
尝试：
conv.clear（）;
Try:
conv.clear();
>
from =" 2";
conv<<来自;
conv> to;
>
from = "2";
conv << from;
conv >to;
问候，
Sumit。
Regards,
Sumit.
Jim Langston写道：
Jim Langston wrote:
from =" 1";
conv<< from;
conv> to;
from =" 2" ;;
conv<<来自;
conv> to;
from = "1";
conv << from;
conv >to;
from = " 2";
conv << from;
conv >to;
无效。
from =" 2" ;;
conv<< from;
没有改变conv的内部缓冲区，conv.str（）仍然返回1。
didn''t work.
from = " 2";
conv << from;
didn''t change the inner buffer of conv, conv.str() still returned "1".
if没有工作，看看是什么
from =" 1 2";
conv<<来自;
conv> to;
conv> to;
if that didnt'' work see what
from = "1 2";
conv << from;
conv >to;
conv >to;
这是有用的。
this worked.
给你。
您可能需要在两者之间重置字符串流，但我从未有过这个
问题。
gives you.
You may need to reset the stringstream in between, but I''ve never had that
problem.
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