Sorting problem

[olexy46]

I am new to c++ programming and i need some help.

I was able to read the text file and sort the list stated below using bubblesort but i don't know how to add up the total sum of the quantity acquired and sort the list in a decreasing alphabetical order without repeating the elements of each product with the same name? Thanks

NAME CATEGORY QUANTITY
walnuts 8 50
pasta 3 7
cheese 2 15
bread 1 10
salad 4 100
pizza 5 15
apples 6 16
cherries 7 22
bread 1 20
cheese 2 5
bread 6 20
pasta 3 5
bread 1 15


LList<Item> Lproducts;
ifstream myfile("products.txt");
string name;
int category;
int quantity;
if (myfile.is_open()) {
while (!myfile.eof()) {
myfile >> name >> category >> quantity;
Item temp(name, category, quantity);
Lproducts.append(temp);
}
}
else
{
cout << "Error of opening of file" << endl;
return -1;
}
myfile.close();

bubblesort(Lproducts);
cout << endl << "print the ordered list" << endl;
lprint(Lproducts);

[keskiverto]

First, posting code with code tags and intuitive indentation helps everyone.
See http://www.cplusplus.com/articles/jEywvCM9/

Second, we can only guess what the LList, bubblesort() and lprint() are.

Third, inherent in every sorting algorithm there is a use of a test, condition, predicate, question:
Are A and B in desired order?
How and when the algorithms test that, is up to them.
The standard library std::sort lets the user to supply a test. See http://www.cplusplus.com/reference/algorithm/sort/
You can either make your bubblesort more general (like the std::sort), or make tweaked copies (bad for learning).

Fourth ... I finally believe that I understand your question ... make a second list (e.g. Sproducts).
Look at each item in Lproducts.
IF that product is not yet in Sproducts, THEN add the item to Sproducts.
ELSE add quantity to the existing item in Sproducts.

[olexy46]

I'll get use to the format with time...infact this is my first thread.
Thanks anyway Keskiverto.

I came across this code and included it between the "item temp" line and the "Lproducts.append(temp)" line.

It worked fine but i don't understand how to create it.


int found = find(Lproducts, temp);
if (found!=-1)
{
Lproducts.moveToPos(found);
Item old = Lproducts.getValue();
old.setnumber(old.getnumber() + number);
Lproducts.remove();
Lproducts.insert(old);

[Enoizat]

Hints:

// I was able to read the text file and sort the list stated below using 
// bubblesort but i don't know how to add up the total sum of the quantity 
// acquired and sort the list in a decreasing alphabetical order without 
// repeating the elements of each product with the same name? Thanks
// NAME CATEGORY QUANTITY
// walnuts 8 50
// pasta 3 7
// cheese 2 15
// bread 1 10
// salad 4 100
// pizza 5 15
// apples 6 16
// cherries 7 22
// bread 1 20
// cheese 2 5
// bread 6 20
// pasta 3 5
// bread 1 15
#include <fstream>
#include <iostream>
#include <limits>
#include <set>
#include <sstream>
#include <string>

class Item {
public:
    Item(std::string name_arg, int category_arg, int quantity_arg);
    bool operator<(const Item& other) const;
    friend std::ostream& operator<<(std::ostream& os, const Item& rhs);
    std::string name;
    int category {},
        quantity {};
};

Item::Item(std::string name_arg, int category_arg, int quantity_arg)
    : name {name_arg}, category {category_arg}, quantity {quantity_arg}
    {}

bool Item::operator<(const Item& other) const
{ return name < other.name; }

std::ostream& operator<<(std::ostream& os, const Item& rhs)
{
    return (os << "Product name: " << rhs.name
               << "; category: " << rhs.category
               << "; available quantity: " << rhs.quantity << '\n');
}


std::set<Item>& loadFromFile(std::ifstream& source, std::set<Item>& catalog);
void waitForEnter();


int main()
{
    std::string filename("products.txt");
    std::ifstream infile(filename);
    std::set<Item> products;
    loadFromFile(infile, products);
    for(const auto& p : products) { std::cout << p; }
    waitForEnter();
    return 0;
}


std::set<Item>& loadFromFile(std::ifstream& source, std::set<Item>& catalog)
{
    std::string line;
    while(std::getline(source, line)) {
        std::stringstream tmpss(line);
        int category {}, quantity {};
        tmpss >> line >> category >> quantity;
        Item tmp_item(line, category, quantity);
        auto insertion = catalog.insert(tmp_item);
        if(!insertion.second) {
            tmp_item.quantity += (insertion.first)->quantity;
            catalog.erase(insertion.first);
            catalog.insert(tmp_item);
        }
    }
    return catalog;
}


void waitForEnter()
{
    std::cout << "\nPress ENTER to continue...\n";
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
}

output:

Product name: apples; category: 6; available quantity: 16
Product name: bread; category: 1; available quantity: 65
Product name: cheese; category: 2; available quantity: 20
Product name: cherries; category: 7; available quantity: 22
Product name: pasta; category: 3; available quantity: 12
Product name: pizza; category: 5; available quantity: 15
Product name: salad; category: 4; available quantity: 100
Product name: walnuts; category: 8; available quantity: 50

Press ENTER to continue...