C++ - 重复使用istingstream
我有一个代码用于读取在线存储的带有浮点数的文件，如下所示：“3.34|2.3409|1.0001|...|1.1|”。我想使用 istringstream 读取它们，但它无法按我的预期工作：
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++;
}
在标记点中，行仅第一次复制到单独的流中。在下一次迭代中它不起作用并且什么也不做。我预计可以使用更多次，而无需在每次迭代中构造新的 istringstream 对象。
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++;
}
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.
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将行设置到 istringstream...
... 通过调用重置它
这会清除在上一次迭代中或通过设置字符串设置的任何 iostate 标志。
http://www.cplusplus.com/reference/iostream/ios/clear/
After setting the row into the istringstream...
... reset it by calling
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/
您需要在
separate.str(row)之后添加separate.clear();行来清除状态位，否则eofbit会得到设置和后续读取失败。You need to add a
separate.clear();line afterseparate.str(row)to clear the status bits, otherwise theeofbitgets set and subsequent reads fail.