My first time here. It still seems impossible that people would help each other out like this online. But I am giving it a try as I can't speak English well enough to ask questions in class... Any help is truly appreciated!! I hope the code doesn't look like a mess as it is my best, for now.
An ISBN (International Standard Book Number) identifies a unique publication. An ISBN is ten digits. The first nine digits must be decimal digits (0...9). The tenth may a decimal digit or the letter X, according to the checksum, seen below. Three single dashes may be between any of the characters, but an ISBN must not begin or end with a dash.
The last character of an ISBN number is a checksum. The checksum is the determined by the first 9 digits; it is computed by taking modulo 11 (the remainder after dividing by 11) of the sum of each digit multiplied by its position in the ISBN. The letter X corresponds to a value of 10.
Here are two ISBNs and the calculations that show how the check sum is determined:
0-201-88337-6 -> (0*1 + 2*2 + 0*3 + 1*4 + 8*5 + 8*6 + 3*7 + 3*8 + 7*9) mod 11 = 6
1-57231-866-X -> (1*1 + 5*2 + 7*3 + 2*4 + 3*5 + 1*6 + 8*7 + 6*8 + 6*9) mod 11 = 10 (X)
I have encountered a few problems. I know I need to use the
for statements in the isbnCheckForUser and isbnCheckForFile functions. But I don't know how to or what to filter out first to eventually get to the "checksum" validation. I am also unclear about the use of fstream. I do not know how to use the .txt file shown below for the program.
here's the content of the isbntest.txt file:
6
0-201-88337-6
0-13-117334-0
157231--866-X
-013-117334-0
0821211315
1-57231-866-X
Here's my code so far:
CODE
#include <iostream>
#include <fstream> // REQUIRED FOR FILE STREAMS
#include <cstdlib> // FOR DEFINITION OF EXIT_FAILURE
#include <cctype>
#include <string>
using namespace std;
// ASSOCIATE STREAMS WITH EXTERNAL FILE NAMES
#define inFile "isbntest.txt" // LINKED ISBN FILE (LIST) SOURCE
// FUNCTIONS USED
void menuPrompt (); // MAIN MENU USER INSTRUCTION
void userVal (); // MANUAL INPUT VALIDATION
int readFile (); // LINKED FILE VALIDATION
bool isbnCheckForUser (string isbn); // ISBN VALIDATION FUNCTION FOR USER INPUT
bool isbnCheckForFile (string isbn); // ISBN VALIDATION FUNCTION FOR FILE INPUT
int main ()
{
char choice; // INPUT-MAIN MENU CHOICE
do
{
menuPrompt ();
cin >> choice;
switch (choice)
{
case '1':
userVal ();
break;
case '2':
readFile ();
break;
case '3':
cout << "Thank you for using ISBN-Check. Have a nice day!" << endl;
break;
default:
cerr << "Oops! Incorrect selection. Please try again." << endl;
}
}
while (choice != '3');
system ("pause");
return 0;
}
void menuPrompt ()
{
cout << "Welcome to ISBN-Check." << endl;
cout << "This program will verify the format of your ISBN(s)." << endl;
cout << "To manually input the ISBN(s), enter 1." << endl;
cout << "To verify the ISBN(s) from the linked .txt file, etner 2." << endl;
cout << "When you're done, enter 3 to exit the program." << endl;
}
void userVal ()
{
char subchoice; // INPUT- SUB MENU CHOICE
string isbn; // INPUT- ISBN STRING
do
{
cout << "Enter an ISBN:";
cin >> isbn;
isbnCheckForUser ();
if (isbnCheckForUser () = true)
cout << "This is a valid ISBN." << endl;
else
cout << "This is NOT a valid ISBN." << endl;
cout << endl;
cout << "To go back to the main menu, enter 1." << endl;
cout << "To continue manually inputting ISBN(s), enter any digit besides 1." << endl;
cin >> subchoice;
}
while (subchoice != '1');
}
int readFile ()
{
ifstream fin;
fin.open (inFile);
if (fin.fail ())
{
cerr << " ERROR: Cannot open " << inFile << " for input. " << endl;
return EXIT_FAILURE; // FAILURE RETURN
}
fin >> isbn;
isbnCheckForFile ();
if (isbnCheckForFile () = true)
cout << "This is a valid ISBN." << endl;
else
cout << "This is NOT a valid ISBN." << endl;
}
bool isbnCheckForUser (string isbn)
{
}
bool isbnCheckForFile (string isbn)
{
}
5 Nov, 2007 - 09:31 PM
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