Help with understanding this code?

[plop442]

Can you please help me with some code? I cant understand some part of it.
<
#pragma once

#include<iostream>
#include<string>
#include<fstream>
#include<vector>
#include<algorithm>

using namespace std;

class SalesData{
private:
ifstream inputfile;
ofstream outputfile;
vector<int> salesrecords;
public:

void loadDataFromFile(string filename){

ifstream infile;
infile.open ("sales.txt");
string line;
//this loop will read the file line by line and store each value in the sales records vector by changing that reading string value to int
while (getline(infile, line))
{
//This declares the character array to store the value of reading line
char arr[line.size()];
//This copies the string into character array
for(int i=0;i<line.size();i++)
arr[i] = line[i];
//This converts the character array into integer
int val=atoi(arr);
//This stores the above converting value into sales records
salesrecords.push_back(val);

}
//This closes the file
infile.close();
}

void saveBarChartToFile(string filename){
ofstream myfile;
//This opens the file
myfile.open ("graph.txt");
//This writes the header to the file
myfile<<"SALES BAR CHART\n(each * equals £100)"<<endl;
// cout<<"SALES BAR CHART\n(each * equals £100)"<<endl;
for(int i=0;i<salesrecords.size();i++){
//because 1 * is 100 pounds, we divide the value by 100 to get the number of stars for that value
int n=salesrecords[i]/100;
//This writes to the file the store number
myfile<<"Store "<<i+1<<": ";
// cout<<"Store "<<i+1<<": ";

//This writes to the file the number of stars
for(int j=0;j<n;j++){
myfile<<"*";
// cout<<"*";
}
myfile << "\n";
// cout<<endl;
}
//This makes sure the file closes
myfile.close();

}
};
//this is the main function
int main()
{

SalesData ob;
ob.loadDataFromFile("sales.txt");
ob.saveBarChartToFile("graph.txt");

}
>

Can you please explain to me, what the code does from while loop, to the infile.close function at the top.

[gunnerfunner]

According to the comments that come with the code, infile is read line by line into a char array which is then converted to an int used std::atoi
However it appears that the file contains only numbers in which case you can read it directly into a temporary integer variable and then push_back this variable into std::vector<int> salesrecords:

    int temp{};//temporary int variable
    while (infile >> temp)//read file into temp
    {
        if (infile)//make sure file is still open
        {
            salesrecords.push_back(temp);//populate salesrecords
        }
    }