Hello All,
This is a student assignment. So I don't want the complete answer just a hint or maybe a bumb on the head cause I'm doing it the wrong way. Assume I haven't done anything braindead like not include a header etc... I can post the whole code if you like/need it but I'm trying to spare the forum :)
Got a product structure...
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struct product {
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string id;
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string description;
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int quantity;
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double wholesale;
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double retail;
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Date* date_added;
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};
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Got a vector of products and a file for the data...
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vector<product> Inventory;
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ifstream inFile; //Input data file
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ofstream outFile; //Output report file
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Saved all the products to a tab delimited file, one product to each line using for_each...
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for_each(Inventory.begin(), Inventory.end(), save_product(&outFile));
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class save_product:public std::unary_function<product, bool>
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{
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private:
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ostream* m_os;
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public:
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save_product( ostream* os ){ m_os = os; }
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bool operator()( const product& element )
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{
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bool ret_val = false;
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// save element in tab delimited format
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*m_os << element.id.c_str()
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<< "\t" << element.description.c_str()
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<< "\t" << element.quantity
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<< "\t" << element.wholesale
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<< "\t" << element.retail
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<< "\t" << element.date_added->get(2) // write date in month/day/year format
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<< "/" << element.date_added->get(1)
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<< "/" << element.date_added->get(3)
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<< "\r\n";
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if(m_os)
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ret_val = true;
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return ret_val;
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}
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};
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No problem so far. The file is as I want it. But getting the data back into the vector is causing me some problems. I've seen the use of the copy algorithm for copying from a fstream to a vector but I need to tell the iterator to use tabs to delimit the text.... I wrote a functor load_product but what algorithm could I use to read the file in with...
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// Copy doesn't quite do what I want with data...
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copy( istream::iterator<T>(inFile), istream::iterator<T>(), back_inserter(Inventory) );
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class load_product:public std::unary_function<product, bool>
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{
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private:
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istream* m_is;
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public:
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load_product( istream* is ){ m_is = is; }
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bool operator()( product& element )
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{
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bool ret_val = false;
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char buffer[maxStringSize];
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stringstream ioConv;
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unsigned int fieldCnt = 0;
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while(m_is && fieldCnt < REC_FIELD_COUNT )
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{
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m_is->getline(buffer,(streamsize)maxStringSize, '\t');
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if(m_is)
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{
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switch( fieldCnt )
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{
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case 0: element.id = buffer; break;
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case 1: element.description = buffer; break;
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case 2: ioConv >> buffer; ioConv << element.quantity; break;
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case 3: ioConv >> buffer; ioConv << element.retail; break;
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case 4: ioConv >> buffer; ioConv << element.wholesale; break;
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default:
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element.date_added->set(buffer, "/");
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break;
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}
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}
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fieldCnt++;
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if( fieldCnt == REC_FIELD_COUNT && m_is ) ret_val = true;
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}
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return ret_val;
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}
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};
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I can do this manually with a while sure but I was hoping for a more elegant/STL way of doing it...
Thanks for any guidance...
John
