Processing values in each text file one at a time c++ - c++

Question

I'm trying to processes values from two text files.One holds a set of chars and the other holds a set of integers.each in their respective places in the text file will amount to one test case.For example the first value that is read in each text file is 1 test case.The values are then used to be checked for variability then Which will then be used as variables through out my code.then in the end prints out a double. The issue is I do not know how to reach that second iteration of test cases. All my code does is read the first values of each text file and prints out the double i need but for only the first test case. As i was typing this out i thought of maybe deleting the values once they are done being used then rerunning the program by having my main in a for loop? suggestions?
#include <iostream>
#include <fstream>
using namespace std;
//function prototypes
char getPackage();
bool vaildPackage(char);
int getHours();
bool validHours(int);
double calculatePakg_A(int);
double calculatePakg_B(int);
double calculatePakg_C(int);
void showBill(double);
int main()
{
char Package = getPackage();
int Hours = getHours();
double bill;
switch (Package)
{
case 'A':bill = calculatePakg_A(Hours);
cout << bill << endl;
break;
case 'B':bill = calculatePakg_B(Hours);
cout << bill << endl;
break;
case 'C':bill = calculatePakg_C(Hours);
cout << bill << endl;
break;
case 'a':bill = calculatePakg_A(Hours);
cout << bill << endl;
break;
case 'b':bill = calculatePakg_B(Hours);
cout << bill << endl;
break;
case 'c':bill = calculatePakg_C(Hours);
cout << bill << endl;
break;
default: cout << "you did not enter a valid Service Plan. \n";
break;
}
return 0;
}
char getPackage()
{
ifstream inputFile;
char a;
inputFile.open("Packages.txt");
do
{
inputFile >> a;
} while (! vaildPackage(a));
return a;
}
bool vaildPackage(char a)
{
return a == 'a' || a == 'A'|| a == 'B' || a == 'b'|| a == 'C' || a == 'c';
}
int getHours()
{
ifstream inFile;
int n;
inFile.open("Hours.txt");
do
{
inFile >> n;
} while (! validHours(n));
return n;
}
bool validHours(int n)
{
return n>=0 && n<= 720;
}
double calculatePakg_A(int hrs)
{
if(hrs <=50)
{
return 15.00;
}
else
{
return (hrs-50) * 2.00 + 15;
}
}
double calculatePakg_B(int hrs)
{
if(hrs <=100)
{
return 20.00;
}
else
{
return (hrs-100) * 1.50 + 20.00;
}
}
double calculatePakg_C(int hrs)
{
if(hrs <=150)
{
return 25.00;
}
else
{
return (hrs-150) * 1.00 + 25.00;
}
}
Package.txt
A a B b C c e c
Hours.txt
50 51 100 101 149 251 750 722

Answer 1

As I'm sure you know, you can read multiple fields from a stream:
ifstream inputFile;
char a;
inputFile.open("Packages.txt");
inputFile >> a;
cout << a << endl;
inputFile >> a;
cout << a << endl;
The reason your code doesn't work is that when control returns from getPackage(), the variable inputFile is deleted, so every time you call that function, it opens the file anew and starts reading from the beginning.
One solution is to make the input stream a static variable, so that it will not be deleted, but will maintain its state from one call to the next:
char getPackage()
{
static ifstream inputFile("Packages.txt");
char a;
inputFile >> a;
return a;
}

Answer 2

I think the only issue here is this.
In the function getPackage()
inputFile.open("Packages.txt");
This opens the file every time you call this function
Due to this, this function is reading the first entry (only) every time.
The same issue with getHours function.
One way out is you can read all entries from the file once into a data structure, say vector and iterate through the vector in the main function.
Another way is open the file(s) in main function and introduce a loop in main that calls these functions. Every time they are called, they would return the next entry from the file. This requires passing the opened file ifstream & as an argument to functions getHours and getPackage