separate string and numeric value from a string

sajis997 (109)
hi forum,

The following snippet of code is not doing the task properly. I have large string with the following format:

 
 
 std::string("13 DUP 4 POP 5 DUP + DUP + -")


Separation is a whitespace and should be working with stringstream. But it is not. Please check the following snippet:

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	std::stringstream ss(std::stringstream::in | std::stringstream::out);
	ss << s;

	while (true)
	{
		unsigned long numericValue = 0;
		string operation = "";

		if (ss >> numericValue)
			list.push(numericValue);
		else if (ss >> operation)
		{
                     /*
                         further operation based on the string values
                     */
                }

                if(!ss)
                   break;
        }


The above code just extract the first value with the sample value and then cannot extract the string. Some hint is expected.

Thanks
jlb (4973)
The only time you will try to extract operation is when the stream fails to retrieve numericValue. When a stream fails it stays in failure mode until it is manually reset, and when a stream is in a fail state it will not process more information.

Perhaps something like: 
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	std::stringstream ss(std::stringstream::in | std::stringstream::out);
	ss << s;

	unsigned long numericValue = 0;
	string operation = "";
	while (ss >> numericValue >> operation)
	{
		list.push(numericValue);
             /*
                         further operation based on the string values
             */
            
        }



sajis997 (109)
Hi ,

But what about the format "+ -", where you have no numeric value in the input at all ?


Thanks
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