Thread: parseString funtion (stream I/O)

In the code provided below, I have written a program (word for word) from my text book. This program reads the text from a file named Accounts.txt and parses the string input to a different format (shown below as well).

My only problem is that when the program executes, I receive the unexpected error "Error, parsing string" (also shown below). After I used my debugger, I stepped into the function parseString() and put a watch on all the values. The value balance was the only one not receiving the correct input (something really wacky....like 5.1233242523532e-308....should be 56.6).

I need to know why I am getting this error.

The text book I am currently using has a few typo's here and there, but I'm still new to C++ and do not know if I could pick any out of the displayed code.

If anyone has any questions about the code or my question, please ask.

thanks in advance!

parseString funtion

Code:

// parseAccountInfo - read a passed buffer as if it were
//                    an actual file - read the following
//                    format:
//                    name, account balance
//                    return true if all worked well
bool parseString(char* pString, char* pName, int arraySize,
                    long& accountNum, double& balance)
{
    //associate an istrstream object with the input
    //character string
    istringstream inp(pString);
    
    //read up to the comma seperator
    inp.getline(pName, arraySize, ',');
    
    //now the account number
    inp >> accountNum;
    
//balance not receiving correct value...
    //and the balance
    inp >> balance;
    
    //return the error status
    return !inp.fail();
}

....now main

Code:

int main(int nNumberOfArgs, char* pszArgs)
{
    //get a file stream
    ifstream* pFileStream = new ifstream("Accounts.txt");
    if(!pFileStream->good())
    {
        cout << "Can't open Accounts.txt" << endl;
        system("PAUSE");
        return 0;
    }
    
    //read a line out of file, parse it and display results
    for(;;)
    {
        //add a divider
        cout << "========================" << endl;
        // read a buffer
        char buffer[256];
        pFileStream->getline(buffer, 256);
        if(pFileStream->fail())
        {
                break;
        }
        
        //parse the individual fields
        char name[80];
        long accountNum;
        
        double balance;
       //using debugger, I step into function below
        bool result = parseString(buffer, name , 80,
                                        accountNum, balance);
                                        
        //output the results
        //program goes into if statement below....result returned false
        cout << buffer << "\n";
        if (result == false)
        {
                cout << "Error parsing string\n";
                continue;
        }
        cout << "name = " << name << ","
             << "account = " << accountNum << ", "
             << "balance = " << balance << endl;
             
        //put the fields back together in a different
        //order (inserting the 'ends' makes sure the
        //buffer is null terminated
        ostringstream out;
        out << name << ", "
            << balance << " "
            << accountNum << ends;
    
        //output the result - istringstream also works with
        //the string class but I have been staying with
        //character arrays until the discussion of the templates
        string oString = out.str();
        cout << oString << "\n" << endl;
    }
    system("PAUSE");
    return 0;
}

the text file i'm using is called "Accounts.txt" and is located in the same directory as executable.

File format for Accounts.txt

Code:

Chester, 12345, 56.60,\n

what the output statement looks like now:

Code:

========================
Chester, 12345, 56.60,\n
Error parsing string
========================

what should happen:

Code:

========================
Chester, 12345, 56.60
name = Chester, account = 12345, balance = 56.6
Chester, 56.6, 12345
========================

Never mind, I got it.

In the text file Accounts.txt, the format should have been this:

Code:

Chester, 12345 56.60\n

The comma between the account number and balance should have not been there. I still do not know why though. If you want, you can explain that part to me.

Thanks!

okay, that seems pretty self explanatory. The book did not provide these files on a cd and I was trying to duplicate a file that the book used...considering that they said thats what the file looked like...I was just confused

thanks though