Stopping file input when a certain word is encountered - c++

Question

I'm working on a c++ program that is supposed to eventually create a cross-reference table from a paragraph of words read in from a file using hashing. Right now I'm mainly working on reading in the input from the file and making sure the hash function is working properly.
Here a little more specifics on this portion of the problem:
The program is supposed to read in a paragraph from a file one word at a time until it reaches a "word" consisting of 10 "*"s. Below this line of *s are a few more lines of words that will be used to test the program later on.
With the code I have written, everything appears to be working properly (I've used the formula to calculate the index of a couple of the words and am getting the same answer as is being displayed), however, I'm not sure how to get the input to stop when I reach the line of 10 *s. So while this seems to be reading the file in correctly and performing the right calculations, it's performing these calculations for every word in the file.
Here's the code I've written:
#include <iostream>
#include <fstream>
using namespace std;
int hash(string word) {
int firstOff = word[0];
int lastOff = word[word.size() - 1];
int index = (firstOff * 256 + lastOff) % 23;
cout << index << endl;
return index;
}
int main() {
ifstream file;
file.open("prog7.dat");
if(!file.is_open()) {
cerr << "Error opening " << file << endl;
}
string word;
while(file >> word) {
hash(word);
}
}
Here's the output I'm getting:
12
6
17
21
1
21
12
14
11
12
7
14
16
10
2
22
19
21
22
7
7
12
21
21
3
9
3
12
14
14
0
3
21
7
6
7
12
7
17
6
2
16
21
7
14
And in case it helps, here's the file I'm using for the input:
the relative lack of acceptance
of these products in the
corporate marketplace is
due less to technical than
to political factors the
availability of this technology
threatens the perks privileges
and traditions of corporate
management
**********
the
political
lack
relative
less
forgive
tradition
factors
more
Can anyone help me out? I'd really appreciate it.

Answer 1

You can simply check for the word in the while condition:
while(file >> word && word != "**********") {
hash(word);
}
You could also break the loop when you reach the word (if you prefer how it looks).
while(file >> word) {
if (word == "**********") break;
hash(word);
}

Answer 2

Can also use an istream_iterator such as
#include <iostream>
#include <string>
#include <iterator>
#include <fstream>
using namespace std;
int main()
{
ifstream file("prog7.dat");
istream_iterator<string> it(file);
while(*it != "**********")
hash(*it++);
}