如何检查StringStream变量是否为空？ [英] How do I check if a StringStream variable is empty/null?

问题描述

这里是一个简单的问题。

这里有更多的信息：

/ p>

  stringstream report_string; 
 
 report_string<< some string here ...; 
 

在我的代码中，有各种条件为report_string变量赋值。

我想检查它是否被分配了一个值。

解决方案

code> myStream.rdbuf（） - > in_avail（）可用于获取可从 stringstream ，你可以使用它来检查你的 stringstream 是否为空。我假设你不是真的试图检查值 null 。

例如，如果你想从 stringstream 中提取 int ，然后查看是否有任何剩余字符（即非数字）您可以检查 myStream.rdbuf（） - > in_avail（）== 0 。

类似于你想做什么？

编辑：我可以使用这个方法看到你刚刚更新你的问题，因为我发布。

Just a quick question here guys. I've been searching to no avail so far.

Thanks!

A bit more info here:

stringstream report_string;

report_string << "some string here...";

In my code itself are various conditions for assigning values to the report_string variable.

I'd like to check whether it was assigned a value or not.

解决方案

myStream.rdbuf()->in_avail() can be used to get the count of available characters ready to be read in from a stringstream, you can use that to check if your stringstream is "empty." I'm assuming you're not actually trying to check for the value null.

For example if you want to extract an int from a stringstream and then see if there were any left over characters (ie. non-numeric) you could check if myStream.rdbuf()->in_avail() == 0.

Is that something similar to what you're trying to do? I'm not sure if there's better ways but I've done this in the past and it's worked fine for me.

EDIT: I see you just updated your question as I posted.

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