如何强制std :: stringstream运算符>>读取整个字符串？ [英] How to force std::stringstream operator >> to read an entire string?

问题描述

如何强制std :: stringstream运算符>>读取整个字符串而不是停在第一个空格？

How to force std::stringstream operator >> to read an entire string instead of stopping at the first whitespace?

我有一个模板类存储从文本文件读取的值：

I've got a template class that stores a value read from a text file:

template <typename T>
class ValueContainer
{
protected:
  T m_value;

public:
  /* ... */
  virtual void fromString(std::string & str)
  {
    std::stringstream ss;
    ss << str;
    ss >> m_value;
  }
  /* ... */
};

我尝试设置/取消设置流标志，但没有帮助。

I've tried setting/unsetting stream flags but it didn't help.

澄清

类是一个容器模板，可以自动转换到T类型。只有一个模板的实例，它也必须支持其他类型。这就是为什么我要强制操作符>>模仿std :: getline的行为。

The class is a container template with automatic conversion to/from type T. Strings are only one instance of the template, it must also support other types as well. That is why I want to force operator >> to mimic the behavior of std::getline.

推荐答案

不满足我们的要求当T =字符串，我们可以写一个特定的函数为[T = string] case。这可能不是正确的解决方案。

As operator >> is not satisfying our requirement when T=string, we can write a specific function for [T=string] case. This may not be the correct solution. But, as a work around have mentioned.

如果不能满足您的要求，请更正我。

Please correct me if it won't satisfy your requirement.

我写了一个示例代码如下：

I have written a sample code as below:

#include <iostream>
#include <sstream>
#include <string>

using namespace std;

template <class T>
class Data
{
    T m_value;
    public:
    void set(const T& val);
    T& get();
};

template <class T>
void Data<T>::set(const T& val)
{
    stringstream ss;
    ss << val;
    ss >> m_value;
}

void Data<string>::set(const string& val)
{
    m_value = val;
}

template <class T>
T& Data<T>::get()
{
    return m_value;
}

int main()
{
    Data<int> d;
    d.set(10);
    cout << d.get() << endl;

    Data<float> f;
    f.set(10.33);
    cout << f.get() << endl;

    Data<string> s;
    s.set(string("This is problem"));
    cout << s.get() << endl;
}

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