I need help with this file problem....???

[brandonjconnor]

Ok, the problem i am having with this problem is specifically number 3.

i don't know how to take a specific piece of info from the file and convert it into a double so i can perform the arithmetic.

please help.



The Bite-a Vite-a vitamin store needs an "expert" computer programmer to help keep track of their inventory. The store maintains all their vitamin stock information on disk. The data is organized as follows:
 
The first column contains the vitamin name (A, B, C, etc.)
The second column contains the unit price of a single jar of that particular vitamin.
The third column has the number of jars of that vitamin in the store.
 
For example:
 
A 12.95 23
K 9.99 56
Z 6.99 25
 
Write a C++ program, on the next page, that will do the following:
 
1. Read data from a data file called inventory located on the store’s hard drive in a directory called c:\store. The store inventory fluctuates so you do not know how much data there is to process.
 
2. Call a function that will return the total value of the store’s inventory for that one vitamin product (unit_price * number_of_jars).
 
3. You will also calculate:
i)  The average price of a vitamin
ii) The total inventory (total number of jars)
 
4. Print the output so that it is organized as follows:
 
 
Vitamin-- Price-- Inventory-- Total Inventory
--------------------------------------------------
A-- 12.95-- 23-- 297.85
K-- 9.99-- 56-- 559.44
Z-- 6.99-- 25-- 174.75
 
The average price for a vitamin is: $9.98
The total store inventory is 104 jars of vitamins
 

[ciphermagi]

This seems like simple division and addition to me. What, specifically, are you having trouble with?

[brandonjconnor]

my problem isn't the arithmetic, it's the fact that i have to extract the numbers from a txt file, i don't know how to do that.

i am searching a little on google and found something that would go like this:

birds>>birdname>>price>>inventory;

i think that might extract the specific values and put them into variables but now how do i do it for specific lines.

[ciphermagi]

This should be a good starting point for you. Once you've gone over this a little bit, you should have a better understanding of what you're looking at.

http://www.cplusplus.com/doc/tutorial/files/

[brandonjconnor]

ok this is what i have so far...

#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream vitamins;
int price, numofvitamins;
char vname[25];
vitamins.open("inventory.txt");
if(!vitamins)
{
	cout<<"File Not Found";
	return 1;
}
vitamins>>vname>>price>>numofvitamins;
cout<<"Vitamin\tPrice\tInventory\tTotal Inventory\n";
cout<<vname<<'\t'<<price<<'\t'<<numofvitamins<<'\t'<<price*numofvitamins<<'\n';

return 0;
}

i still need help... line 15 above only takes the info from the first line of the txt file, how do i get it from the second and third line.

also when i run this program my inventory shows up as -858993460, why is it doing that.


p.s. my inventory.txt file reads as follows:

A 12.95 23
K 9.99 56
Z 6.99 25

[ne555]

only takes the info from the first line of the txt file, how do i get it from the second and third line.

You keep reading, till there is nothing to read.
¿How will you do it if the input comes from the user?

when i run this program my inventory shows up as -858993460, why is it doing that.

Because the price is writted as a double, but you are using an integer to read it.
A 12.95 23

'A' -> name
12 -> price
'.' -> numofvitamins //fail 

[brandonjconnor]

You keep reading, till there is nothing to read.
¿How will you do it if the input comes from the user?

umm... i have no idea, i probably know, but i am just blanking out right now.

sorry for being so slow, i am still VERY new to c++

is there any way you could show me an example on how to do this, you don't have to necessarily answer this problem

Because the price is writted as a double, but you are using an integer to read it.
A 12.95 23

wow... i feel like a fool now, thank you for that.

[ne555]

while( input>>name>>price>>quantity ){
  //process 1 product
}

This problem can be done online.

But you could also store the info in a container, to use it later.

vector<product> container;
while( input>>name>>price>>quantity )
  container.push_back( product(name,price,quantity) );

//Now you have all the products in the vector 

[brandonjconnor]

whewww, i figured it out.

i would like to thank everybody who helped me out with this, all of you brought one step closer to figuring it out.... lol

anyway this is what i came up with:

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
void totalinventory(double, double);
int main()
{
ifstream vitamins;
double price, numofvitamins, sum, avg, totalinv, count;
char vname[25];
vitamins.open("inventory.txt");
count=0;
if(!vitamins)
{
	cout<<"File Not Found";
	return 1;
}
sum=0;
totalinv=0;
cout<<fixed<<showpoint<<setprecision(2);
cout<<"Vitamin\tPrice\tInventory\tTotal Inventory\n";
while (!vitamins.eof())
{
vitamins>>vname>>price>>numofvitamins;
cout<<vname<<'\t'<<price<<'\t'<<numofvitamins<<"\t\t";
totalinventory(price, numofvitamins);
count++;
sum=sum+price;
totalinv=totalinv+numofvitamins;
}
avg=sum/count;
cout<<"\nThe average price for a vitamin is: "<<avg<<endl;
cout<<"The toal store inventory is "<<totalinv<<" jars of vitamins\n\n";
return 0;
}
 void totalinventory(double x,double y)
 {
	 double z;
	 z=x*y;
	 cout<<z<<endl;
 }