Thread: Initializing an istringstream

  1. #1
    Registered User
    Join Date
    Oct 2005

    Initializing an istringstream

    I have a string object and an istringstream object and I was wondering if it was possible to set the string data in the stringstream using a member function.

    I know you can initialize an istringstream like this:
    istringstream somestream(somestring);
    But I wasn't able to find a straightforward way to recycle the stringstream with a member function. The only way I was able to think of was:
    	istringstream* somestream;
    	somestream = new istringstream(somestring);
    	//do something with the stream
    	delete somestream;
    	somestream = new istringstream(someotherstring);
    	//do something else with the stream
    	delete somestream;
    It works, but I have a feeling there's a better way to do it. But how?

  2. #2
    Devil's Advocate SlyMaelstrom's Avatar
    Join Date
    May 2004
    Out of scope
    There is a str() member function available for both istringstreams and ostringstreams. EDIT: Sorry, I'll clarify better, this can be used in conjunction with the inherited clear() function.
    #include <iostream>
    #include <sstream>
    int main() {
        std::istringstream inStr;
        float PI, E;
        inStr >> PI;
        inStr >> E;
        std::cout << PI << std::endl << E;
        return 0;
    You have to clear the stream because after you read in the whole thing, the eof-flag is set to true.
    Last edited by SlyMaelstrom; 05-11-2006 at 08:47 PM.
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  3. #3
    Registered User
    Join Date
    Oct 2005
    Thank you. That worked wonderfully.

    May your milk forever flow like the galaxy from the udders of cows.

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