C++ vector coding

[chloejones25]

I have been asked to create a program that needs to read sales values from a sales text file and therefore will output a bar chart representing these values to a graph text file. the bars need to be created in the bar graph by displaying a row of asterisks. Each asterisk needs to represent £100 of sales

This is the coding I have so far, however i am confused as to how to include a vector within the program, and when i run the program no data is being displayed from the text file.

#pragma once // stops duplicate library includes 
#include <iostream>
#include <string>
#include <fstream>
#include <vector>

using namespace std;

class SalesData
{
private:
	ifstream inputfile;
	ofstream outputfile;
	vector<int> salesData;
public:
	void loadDataFromFile(string filename);
	void saveBarChartToFile(string filename);
};



void SalesData::loadDataFromFile(string filename)
{
	//loop to read in 
	ifstream sales;
	int SalesData;

	inputfile.open("Sales.txt", ios::in);

	if (!inputfile) return; //check to see if file exists 

	while (inputfile >> SalesData) cout << SalesData << endl;	
	{
		//vector<int> myintvector;
		//for (int i = 0; i < 10; i++)
		//{
			//myintvector.push_back(i);
			//cout << SalesData << endl; //when EOF is reached, (input file >> salesdata) returns false 
		//}
	}
	inputfile.close();

}



void SalesData::saveBarChartToFile(string filename)
{
	//loop to read out 
	ofstream graph; //ofstream is an Output File Stream
	
	graph.open("Graph.txt", ios::out);
	graph << "Sales bar chart" << endl;
	graph << " (each * equals £100)" << endl;
	graph.close(); //close stream. You always have to close what you open 
	
}


int main()
{
	SalesData MyData;
	MyData.loadDataFromFile("Sales.txt");
	MyData.saveBarChartToFile("Graphs.txt");

	system("Pause");
	return 0;
}

[JLBorges]

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <cmath> // std::round

class SalesData
{
    private: std::vector<double> sales ;

    public:
        void loadDataFromFile( std::string filename );
        void saveBarChartToFile( std::string filename ) const;
};

void SalesData::loadDataFromFile( std::string filename )
{
    std::ifstream inputfile(filename); // open the file for input

    // add each sales amount read from the file to the vector
    double sales_amount ;
    while ( inputfile >> sales_amount ) sales.push_back(sales_amount) ;
}

void SalesData::saveBarChartToFile( std::string filename ) const
{
    std::ofstream graph(filename); // // open the file for output
    graph << "Sales bar chart\n (each * equals £100)\n" ;

    for( double sales_amount : sales ) // for each value in the vector
    {
        // number of asterisks == sales_amount/100 rounded to the nearest integer
        const std::size_t num_asterisks = std::round( sales_amount / 100 ) ;

        // write a string containing num_asterisks asterisks and a newline after that
        graph << std::string( num_asterisks, '*' ) << '\n' ;
    }
}

int main()
{
    SalesData MyData;
    MyData.loadDataFromFile("Sales.txt");
    MyData.saveBarChartToFile("Graph.txt");
}

[chloejones25]

Thank you but I have tried this and still when the program is being run it is just saying "Press any key to continue" and no numbers are being displayed.

[JLBorges]

> "will output a bar chart representing these values to a graph text file"

MyData.saveBarChartToFile("Graph.txt"); writes the bar chart to the file "Graph.txt".

Open the file in a text editor to see its contents;
or add this line as the last statement in main() to dump the contents of "Graph.txt"to stdout.
std::cout << std::ifstream("Graph.txt").rdbuf() ;

[gunnerfunner]

OP: if problem persists can you show us how Sales.txt looks like?

[chloejones25]

1000
500
1200
600
200
this is what is contained in the Sales.txt file. I have used the coding that JLBorges has given me but it is saying that num_Asterisks is undefined even though the coding is practically the same?
This is my coding so so far.

#pragma once // stops duplicate library includes 
#include <iostream>
#include <string>
#include <fstream>
#include <vector>

using namespace std;

class SalesData
{
private:
	ifstream inputfile;
	ofstream outputfile;
	vector<double> sales;
public:
	void loadDataFromFile(string filename);
	void saveBarChartToFile(string filename);
};



void SalesData::loadDataFromFile(string filename)
{
	//loop to read in 
	inputfile.open("Sales.txt", ios::in);
		std::ifstream inputfile(filename);
	int salesAmount;
	if (!inputfile) return;
	while (inputfile >> salesAmount) sales.push_back(salesAmount);
	inputfile.close();

}

void SalesData::saveBarChartToFile(string filename)
{
	//loop to read out 

	std::ofstream graph(filename); //ofstream is an Output File Stream
	graph.open("Graph.txt", ios::out);
	graph << "Sales bar chart\n (each * equals £100)\n";
	for (double salesAmount : sales)
		const std::size_t numAsterisks = std::round(salesAmount / 100);
	graph << std::string( numAsterisks, '*') << '\n';
	graph.close(); //close stream. You always have to close what you open 

}


int main()
{

	SalesData MyData;
	MyData.loadDataFromFile("Sales.txt");
	MyData.saveBarChartToFile("Graphs.txt");
	std::cout << std::ifstream("Graph.txt").rdbuf();
	system("Pause");
	return 0;
}

[gunnerfunner]

OP: repeat after me ... when JLBorges sends me a solution I shall not touch even a comma of it but study it super carefully to make myself a better programmer

saying that num_Asterisks is undefined

that's because numAsterisks goes out of scope after the for statetment unless you explicitly scope it as JLBorges did b/w lines 31 and 37 of his/her program and you should do this even for one line of code. You also need to #include <cmath> for std::round (again, as JLBorges did) and do not include the actual file names in the class methods (as s/he did not, see?). These will be passed to the methods in main(). Finally, be aware that #pragma once is non-standard, though widely supported, preprocessor directive https://en.wikipedia.org/wiki/Pragma_once

#pragma once // stops duplicate library includes
#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <cmath>


using namespace std;

class SalesData
{
private:
	ifstream inputfile;
	ofstream outputfile;
	vector<double> sales;
public:
	void loadDataFromFile(string filename);
	void saveBarChartToFile(string filename);
};



void SalesData::loadDataFromFile(string filename)
{
	//loop to read in
	//inputfile.open("D:\\input.txt", ios::in);
		std::ifstream inputfile(filename);
	int salesAmount;
	if (!inputfile) return;
	while (inputfile >> salesAmount) sales.push_back(salesAmount);
	inputfile.close();

}

void SalesData::saveBarChartToFile(string filename)
{
	//loop to read out

	std::ofstream graph(filename); //ofstream is an Output File Stream
	graph << "Sales bar chart\n (each * equals £100)\n";
	for (double salesAmount : sales)
    {
        const std::size_t numAsterisks = std::round(salesAmount / 100);
        graph << std::string( numAsterisks, '*') << '\n';
    }

}


int main()
{

	SalesData MyData;
	MyData.loadDataFromFile("D:\\input.txt");
	MyData.saveBarChartToFile("D:\\output.txt");
	std::cout << std::ifstream("D:\\output.txt").rdbuf();
//	system("Pause");
	return 0;
}

[chloejones25]

This is my final code. No error messages are being produced when I am building the solution. However, when it is running, there is still no data being displayed within the Graph.txt file. Can anyone help me to solve this please?

#pragma once // stops duplicate library includes 
#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <cmath>

using namespace std;

class SalesData
{
private:
	ifstream inputfile;
	ofstream outputfile;
	vector<double> sales;
public:
	void loadDataFromFile(string filename);
	void saveBarChartToFile(string filename);
};



void SalesData::loadDataFromFile(string filename)
{
	//loop to read in 
	std::ifstream inputfile("Sales.txt");
	int salesAmount;
	if (!inputfile) return;
	while (inputfile >> salesAmount) sales.push_back(salesAmount);
	inputfile.close();

}

void SalesData::saveBarChartToFile(string filename)
{
	//loop to read out 
	std::ofstream graph("Graph.txt"); //ofstream is an Output File Stream
									  //graph.open("Graph.txt", ios::out);
	graph << "Sales bar chart\n (each * equals £100)\n";
	for (double salesAmount : sales)
	{
		const std::size_t numAsterisks = std::round(salesAmount / 100);
		graph << std::string(numAsterisks, '*') << '\n';
		//graph.close(); //close stream. You always have to close what you open

	}
}


	int main()
	{

		SalesData MyData;
		MyData.loadDataFromFile("Sales.txt");
		MyData.saveBarChartToFile("Graphs.txt");
		std::cout << std::ifstream("Graph.txt").rdbuf();
		system("Pause");
		return 0;
	}

[gunnerfunner]

Re-ran it again w/o any problems but just to be sure try removing the filenames from the methods. Also, make sure you actually run the program and not just compile it

[chloejones25]

Sorry what do you mean by remove the filenames from the methods? yeah the program is running

[gunnerfunner]

yeah the program is running

good!

Sorry what do you mean by remove the filenames from the methods?

refer to lines 18 and 27 of JLBorges' - the names of the files are passed to the methods, not hard-coded therein