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Join Date: Feb 2008

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Jennifer84 Jennifer84 is offline

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istringstream

Mar 6th, 2008

I am using istringstream to put strings separated by commas to own std::strings.
I have done this wich works:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
std::string One, Two, Three, Four, Five, Six;
std::string Value = "a,b,c,d,e,f";
istringstream is(Value);
 
while ( getline(is, One, ',') && getline(is, Two, ',') && getline(is, Three, ',') && getline(is, Four, ',') && getline(is, Five, ',') && is >> Six)
   {
	//Action;
   }
std::string One, Two, Three, Four, Five, Six;
std::string Value = "a,b,c,d,e,f";
istringstream is(Value);

while ( getline(is, One, ',') && getline(is, Two, ',') && getline(is, Three, ',') && getline(is, Four, ',') && getline(is, Five, ',') && is >> Six)
   {
	//Action;
   }

So I am extracting Value that consists of 6 strings separated by ",".
Now if I will take "f" away from Value. This will not work. The std::strings One to Five will not be assigned any strings as it is only 5 elements in the string Value now.
Why does this happening ?
Is this possible to make it work when you dont know how many strings you are trying to exctract from Value. The maximum will be 6 though.

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Join Date: Jul 2005

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Lerner

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Re: istringstream

Mar 6th, 2008

Not if the substrings need to go into a rigid set of variables. You could declare an array/vector that could hold up to 6 strings and extract them out of the original string one at a time storing them in the array as you go. In the array they won't be assigned to string variables by the name of One, Two, etc, however.

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Join Date: Feb 2008

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Jennifer84 Jennifer84 is offline

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Re: istringstream

Mar 6th, 2008

Okay, that sounds nice. I know exactly how vectors works and how to assign the elements but what I dont really know how to do, is to exctract each string separated by ',' in my std::string Value.
I know how to do if I know how many strings that are separated but not if I dont know how many strings that is separated by ','
Any idéas how to do that ?
Thanks...

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
std::vector<string> Store(5);
std::string Value = "a,b,c,d,e,f"; //Strings can differ. This example is 6, 
                                   //sometimes it can be 5,4,3,2 or 1
std::vector<string> Store(5);
std::string Value = "a,b,c,d,e,f"; //Strings can differ. This example is 6, 
                                   //sometimes it can be 5,4,3,2 or 1

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Originally Posted by Lerner

Not if the substrings need to go into a rigid set of variables. You could declare an array/vector that could hold up to 6 strings and extract them out of the original string one at a time storing them in the array as you go. In the array they won't be assigned to string variables by the name of One, Two, etc, however.

Last edited by Jennifer84; Mar 6th, 2008 at 6:17 pm.

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mitrmkar

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Re: istringstream

Mar 6th, 2008

This is practially pretty much what Lerner said ...

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
std::string Value = "a,b,c,d,e,f";
istringstream is(Value);
std::string s;
std::vector<string> v;
 
while (getline(is, s, ','))
{
    // add item
    v.push_back(s);
}
// iterate through the vector and output each item ...
for(std::vector<string>::iterator it = v.begin(); it != v.end(); it ++)
{
    cout << *it << endl;
}
std::string Value = "a,b,c,d,e,f";
istringstream is(Value);
std::string s;
std::vector<string> v;

while (getline(is, s, ','))
{
    // add item
    v.push_back(s);
}
// iterate through the vector and output each item ...
for(std::vector<string>::iterator it = v.begin(); it != v.end(); it ++)
{
    cout << *it << endl;
}

Last edited by mitrmkar; Mar 6th, 2008 at 6:22 pm.

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Join Date: Feb 2008

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Jennifer84 Jennifer84 is offline

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Re: istringstream

Mar 6th, 2008

Thank you very much mitrmkar and Lerner. That did solve it. I was not really sure how to continuosly get the next string after each ',' but now I know how to do that.
Thanks...

•

Originally Posted by mitrmkar

This is practially pretty much what Lerner said ...
Help with Code Tags

C++ Syntax (Toggle Plain Text)
std::string Value = "a,b,c,d,e,f";
istringstream is(Value);
std::string s;
std::vector<string> v;
 
while (getline(is, s, ','))
{
    // add item
    v.push_back(s);
}
// iterate through the vector and output each item ...
for(std::vector<string>::iterator it = v.begin(); it != v.end(); it ++)
{
    cout << *it << endl;
}
std::string Value = "a,b,c,d,e,f"; istringstream is(Value); std::string s; std::vector<string> v; while (getline(is, s, ',')) { // add item v.push_back(s); } // iterate through the vector and output each item ... for(std::vector<string>::iterator it = v.begin(); it != v.end(); it ++) { cout << *it << endl; }