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Consolidate daily sales to sales of a month

formatyes (9)
Hello,
I have daily sales imported in a vector of objects

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class adb
private:
	long S_Date = 0;  //  Date yyyymmdd
	double S_Amount = 0;       // Daily sale
public:
	void set_S_Date ( std::string Ardat );
	void set_S_Amount ( std::string Aresum );
	long get_S_Date () const;
	double get_S_Amount () const;
};

//Vector of objects
std::vector<adb>vo_adb ( 1000 );


Now I want to consolidate the daily sales to sales of a month (yyyymm). Do you have an idea how can I do this in an modern way without a C-Array?

Thanks
JLBorges (13770)
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#include <vector>
#include <map>

struct adb {

    long date = 0 ; // yyyymmdd
    double daily_sales_amount = 0 ;
};

// https://en.cppreference.com/w/cpp/container/map
// key: month yyyymm, mapped value: monthly sales
using monthly_sales_map = std::map<long,double> ;

monthly_sales_map consolidate( const std::vector<adb>& daily_sales ) {

    monthly_sales_map monthly_sales ;

    // http://www.stroustrup.com/C++11FAQ.html#for
    // https://en.cppreference.com/w/cpp/language/structured_binding
    for( auto [ date, amount ] : daily_sales ) 
        monthly_sales[ date/100 ] += amount ; // yyyymmdd/100 == yyyymm

    return monthly_sales ;
}
formatyes (9)
thank you and very educationaly for me!
formatyes (9)
Sorry but very difficult for me beginner. But I would be happy if this function would work. A lot of c++ books red and a lot of research in Google … something learned but not enough to solve this hard nut :-)
Also the C++14 Compiler has a Problem with for(Auto[…….


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#include <vector>
#include <map>
#include <iostream>

struct adb
{
	long date = 0 ;
	double daily_sales_amount = 0 ;
};

using monthly_sales_map = std::map<long,double> ;

monthly_sales_map consolidate ( const std::vector<adb>& daily_sales )
{
	monthly_sales_map monthly_sales ;
	for ( auto [ date, amount ] : daily_sales )  //3 different error messages
		monthly_sales[ date/100 ] += amount ;

	return monthly_sales ;
}

int main()
{
	std::vector<adb> sadb ( 5 );
	sadb.at ( 0 ).date = 20181201;
	sadb.at ( 0 ).daily_sales_amount = 321.00;

	sadb.at ( 1 ).date = 20181215;
	sadb.at ( 1 ).daily_sales_amount = 79.00;

	sadb.at ( 2 ).date = 20190101;
	sadb.at ( 2 ).daily_sales_amount = 111.00;

	sadb.at ( 3 ).date = 20181224;
	sadb.at ( 3 ).daily_sales_amount = 100.00;

	sadb.at ( 4 ).date = 20190131;
	sadb.at ( 4 ).daily_sales_amount = 100.00;

????????????

}


Thank you!
keskiverto (10402)
For the error:
You are iterating the elements of the vector. The auto [ date, amount ] does essentially
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adb foo = ...
auto date = foo.date;
auto amount = foo.daily_sales_amount;



The consolidate is a function. How do you usually call a function?
formatyes (9)
on the right way?
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{
	monthly_sales_map monthly_sales ;
	for ( auto& elem : daily_sales )  
		monthly_sales[ elem.date/100 ] += elem.daily_sales_amount ;

	return monthly_sales ;
}

int main()
{
	std::vector<adb> sadb ( 5 );
	sadb.at ( 0 ).date = 20181201;
	sadb.at ( 0 ).daily_sales_amount = 321.00;
………..
	monthly_sales_map erg_map;
	erg_map = consolidate ( const std::vector<adb>& sadb )
	
}
Last edited on
JLBorges (13770)
> Also the C++14 Compiler has a Problem with for(Auto[…….

Structured bindings came with C++17
https://en.cppreference.com/w/cpp/language/structured_binding

Call the function. For example:

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#include <vector>
#include <map>
#include <iostream>

struct adb
{
	long date = 0 ;
	double daily_sales_amount = 0 ;
};

using monthly_sales_map = std::map<long,double> ;

monthly_sales_map consolidate ( const std::vector<adb>& daily_sales )
{
	monthly_sales_map monthly_sales ;
	for ( const auto& elem : daily_sales )
		monthly_sales[ elem.date/100 ] += elem.daily_sales_amount ;

	return monthly_sales ;
}

int main()
{
    // initialise vector 
	std::vector<adb> sadb { {20181201,321.00}, {20181215,79.00}, {20190101,111.00},
	                        {20181224,100.00}, {20190131,100.00} } ;
    
    // call the function, store its result in erg_map
    const monthly_sales_map erg_map = consolidate(sadb) ; 

    for( const auto& kv_pair : erg_map )
        std::cout << kv_pair.first << ' ' << kv_pair.second << '\n' ;
}

http://coliru.stacked-crooked.com/a/81d9b3f8bdfdcc81
formatyes (9)
thank you for your help - I learned a lot!!!! Now I have changed struct to class as data source. 

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#include <vector>
#include <map>
#include <iostream>
#include <sstream>

class adb
{
private:
	long date {};  //  Date invoice
	double daily_sales_amount=0;       
public:
	void set_date ( std::string date );
	void set_daily_sales_amount ( std::string daily_sales_amount );
	long get_date () const;
	double get_daily_sales_amount () const;
	double f_stod ( std::string betrag );
};

void adb::set_date ( std::string date )
{
	this->date = std::stol ( date );
}

long adb::get_date() const 
{
	return date;
}

void adb::set_daily_sales_amount ( std::string daily_sales_amount )
{

	this->daily_sales_amount = adb::f_stod ( daily_sales_amount );
}

double adb::get_daily_sales_amount() const
{
	return daily_sales_amount;
}


using monthly_sales_map = std::map<long,double> ;


monthly_sales_map consolidate ( const std::vector<adb>& daily_sales )
{
	monthly_sales_map monthly_sales ;
	for ( const auto& elem : daily_sales )
		monthly_sales[ elem.get_date()/100 ] += elem.get_daily_sales_amount() ;

	return monthly_sales ;
}

int main()
{
	// initialize vector
	std::vector<adb> sadb ( 4 );

	sadb[0].set_date ( "20181201" );
	sadb[0].set_daily_sales_amount ( "400.00" );

	sadb[1].set_date ( "20181225" );
	sadb[1].set_daily_sales_amount ( "200.22" );

	sadb[2].set_date ( "20190125" );
	sadb[2].set_daily_sales_amount ( "100.11" );

	sadb[3].set_date ( "20190131" );
	sadb[3].set_daily_sales_amount ( "99.89" );

	// call the function, store its result in erg_map
	const monthly_sales_map erg_map = consolidate ( sadb ) ;

	for ( const auto& kv_pair : erg_map )
		std::cout << kv_pair.first << ' ' << kv_pair.second << '\n' ;
}


double adb::f_stod ( std::string amount ) //Change amount from string to double
{
	std::vector<char> erg;
	erg.reserve ( 10 );
	int i {0};
	do 
		{
			if ( amount[i] == ',' )
				{
					erg.push_back ( '.' );
				}
			else
				{
					erg.push_back ( amount[i] );
				}
			i++;
		}
	while ( amount[i] != ' ' );

	double derg = 0;

	std::string serg ( erg.begin(), erg.end() );
	std::istringstream stream;
	stream.str ( serg );
	stream >> derg;
	//std::cout << "derg:" << derg << std::endl;
	return derg;
}
Last edited on
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