C ++ - 重复使用istringstream [英] C++ - repeatedly using istringstream

问题描述

我有一个代码，用于读取文件的浮动数字在行存储像这样：3.34 | 2.3409 | 1.0001 | ... | 1.1 |。我想使用istringstream读取它，但它不工作，因为我会期望：

I have a code for reading files with float numbers on line stored like this: "3.34|2.3409|1.0001|...|1.1|". I would like to read them using istringstream, but it doesn't work as I would expect:

  string row;
  string strNum;

  istringstream separate;  // textovy stream pro konverzi

   while ( getline(file,row) ) {
      separate.str(row);  // = HERE is PROBLEM =
      while( getline(separate, strNum, '|') )  { // using delimiter
        flNum = strToFl(strNum);    // my conversion
        insertIntoMatrix(i,j,flNum);  // some function
        j++;
      }
      i++;
    }

在标记点，第一次将行复制到单独的流。在下一次迭代它不工作，它什么也不做。我希望可以使用更多的时间，而不是在每次迭代中构造新的istringstream对象。

In marked point, row is copied into separate stream only first time. In next iteration it doesn't work and it does nothing. I expected it is possible to be used more times without constructing new istringstream object in every iteration.

推荐答案

istringstream ...

After setting the row into the istringstream...

separate.str(row);

...通过调用重置

separate.clear();

这将清除在上一次迭代中设置的任何iostate标志或通过设置字符串。
http://www.cplusplus.com/reference/iostream/ios/clear/

This clears any iostate flags that are set in the previous iteration or by setting the string. http://www.cplusplus.com/reference/iostream/ios/clear/

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