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// Keyboard keys \ |
#include <iostream>
#include <fstream>
#include "Sales_data.h"
using std::cout; using std::cerr; using std::endl; using std::cin;
using std::ifstream; using std::ofstream;
int main(int argc, char *argv[])
{
ifstream input (argv[0]);
ofstream output (argv[1]);
Sales_data total;
if (read(input, total)) {
Sales_data trans; // define trans to work more or the same book
while (read(input, trans)) { // while we get input into trans
if (total.isbn() == trans.isbn()) { // if we are proccessing the same book
total.combine(trans);
} else { // if we get input for another book
print(output, total); // print the results of the previous book
// assign total the value of the new book
total = trans;
}
}
print(output, total); // print the results of the previous book
} else
cerr << "No data?!" << endl;
return 0;
}
#ifndef SALES_DATA_H
#define SALES_DATA_H
#include <iostream>
#include <string>
class Sales_data; // declaration for the following class
std::istream &read(std::istream &, Sales_data &); // declaration for read, used inside the class
class Sales_data {
public:
friend std::istream &read(std::istream &, Sales_data &);
friend std::ostream &print(std::ostream &, const Sales_data &);
friend Sales_data add(const Sales_data &, const Sales_data &);
// CONSTRUCTORS
Sales_data() = default; // needed
Sales_data(const std::string &s, unsigned n, double p) : bookNo(s), units_sold(n), revenue (p*n) {} // if we get a string, unsigned and a double then initialize the members of the class
Sales_data(const std::string &s) : Sales_data(s, 0, 0) {} // if we just get a string as a initializer then assign that to bookNo
Sales_data(unsigned n, double p) : Sales_data("", n, p) {}
Sales_data(std::istream &is) // if we get an istream
{
read(is, *this); // call read to assign the current object
}
std::string isbn() const // funtion to call for the ISBN of the current book
{
return bookNo; // return the book numbers
}
Sales_data& combine (const Sales_data&rhs) // to combine two Objects of Sales_data
{
units_sold += rhs.units_sold; // add the amount of books sold
revenue += rhs.revenue; // for adding the revenue
return *this; // return the object that the funtion was called on
}
public:
inline double avg_price() const // for calculating the average price
{
if (units_sold)
return revenue/units_sold; // return: devide revenue by the amount of units sold
else
return 0; // else return nothing
}
std::string bookNo; // for holding our book number/ISBN
unsigned units_sold = 0; // for holding the amount of books sold
double revenue = 0.0; // for holding the price they were sold at
};
std::istream &read(std::istream &is, Sales_data &item) // funtion for getting input into a Sales_data object
{
double price = 0; // for getting our price that the objects were sold at
is >> item.bookNo >> item.units_sold >> price; // get input
item.revenue = price * item.units_sold; // calculate the revenue
return is;
}
std::ostream &print(std::ostream &os, const Sales_data &item) // funtion for output
{
os << item.isbn() << " " << item.units_sold << " " << item.revenue << " " << item.avg_price(); // print out values
return os; // return the output stream
}
Sales_data add(const Sales_data &lhs, const Sales_data &rhs) // for adding to Sales_data objects
{
Sales_data sum = lhs; // sum for returning
sum.combine(rhs); // combine sum with rhs
return sum; // return the combined object
}
#endif // SALES_DATA_H
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