How do I get my total by adding all my subtotals? - c++

Question

I have my program doing 90% of what I want all that is left to do is get the total by adding all my subtotals and outputting to a file. It my be something simple but I can't seem to find a way to get the total of all my subtotals added together. To be honest, even though I need to make it output into a text file I have not attempted anything yet because I was trying to figure a way to get my total. Would someone mind finding me a solution and explaining it so I get a better understanding.
//Libraries
#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
using namespace std;
int main() {
ifstream theFile("input.txt");
string name;
int units;
double price, subtotal;
cout << "\n" <<string(80, '*') << endl;
cout.width(66); cout << "Inventory Report For Jane Doe International Hardware" << endl;
cout << string(80, '*') << "\n" << endl;
cout << left << setw(20) << "ITEM";
cout << right << setw(20) << "NUMBER OF UNITS";
cout << right << setw(20) << "UNIT COST ($)";
cout << right << setw(20) << "TOTAL VALUE ($)" << endl;
cout << string(80, '-') << "\n" <<endl;
cout << fixed;
cout << setprecision(2);
while (theFile >> name >> units >> price) {
subtotal = units*price;
cout << left << setw(20) << name << right << setw(15) << units << right << setw(20) << price << right << setw(20) << subtotal <<endl;
}
cout << "\n" <<string(80, '-') << endl;
cout <<left << setw(20) << "Inventory Total ($)" << right << setw(55) << "total" <<endl;
return 0;
}
My input text file
Chisel 50 9.99 Hammer 30 15.99 Nails 2000 0.99
Bolts 200 2.99 Nuts 300 1.99 Soap 55 1.89

Answer 1

You need to sum up all subtotals. However, each subtotal is only accessible in its iteration, afterwards, it's lost since you reassign subtotal.
Hence, declare a variable total outside of your while loop, then add the subtotal to the total in each iteration. Thus, add the following line
subtotal = units*price;
total += subtotal;
Now you can print total later on.