Question

C++

Here is a program that to validate the ISBN number from user typed and output "Valid" if the number is valid, and "Invalid" otherwise.

I want to change this program to read the file, and to validate the ISBN number from the file.

Please add comments.

#include <iostream>

#include <string>

using std::cin;

using std::cout;

using std::string;

// remove dashes convert letters to upper case

string normalize(const string &isbn) {

string ch;

for (char i : isbn) {

if (i == '-') {

continue; // if "-" then skip it

}

  

if (isalpha(i)) {

i = toupper(i); // Check uppercase

}

ch += i;

}

return ch;

}

// return the number of digits in to the string

size_t numDigits(string &str) {

size_t numDigits = 0;

for (char ch : str) {

if (isdigit(ch)) {

++numDigits;

}

}

return numDigits;

}

enum ValidationCode {

Ok, // validation passed

NumDigits, // wrong number of digits

ExtraChars // extra characters in isbn

};

enum ValidationCode validate(string &isbn) {

string normal = normalize(isbn);

size_t count = numDigits(normal);

if (count != 10) {

return NumDigits;

}

if (normal.size() == 10 || normal.size() == 11 && normal[10] == 'X') {

return Ok;

}

return ExtraChars;

}

int main() {

string str;

while (cin >> str) {

switch (validate(str)) {

case Ok:

cout << str << " is a valid isbn\n";

break;

case NumDigits:

cout << str << " doesn't have 10 digits\n";

break;

case ExtraChars:

cout << str << " has extra characters\n";

break;

default:

cout << "ERROR: validate(" << str << ") return an unknown status\n";

break;

}

}

}

isbn_data.text

1-214-02031-3

0-070-21604-5

2-14-241242-4

2-120-12311-x

0-534-95207-x

2-034-00312-2

1-013-10201-2

2-142-1223

3-001-0000a-4

done

Answer 1

Hello, here is the completed code you wanted. Every important statement is explained using comments. Please check and let me know if you have any doubts. Thanks.

CODE

#include <iostream>
#include <string>
#include<fstream>

using namespace std;

// function remove dashes convert letters to upper case
string normalize(const string &isbn)
{
   string ch;
  
   //loop to remove dashes convert letters to upper case
   for (char i : isbn)
   {
       // if "-" then skip it
       if (i == '-')
       {
           continue;
       }
       // Check uppercase
       if (isalpha(i))
       {
           i = toupper(i);
       }
       //appending to ch
       ch += i;
   }
   //returns isbn code with dashes removed and all letters are in upper case
   return ch;
}

// function for return the number of digits in the string
size_t numDigits(string &str)
{
   size_t numDigits = 0;
  
   //loop to find number of digits in the string
   for (char ch : str)
   {
       //if digit
       if (isdigit(ch))
       {
           //incrementing numDigits
           ++numDigits;
       }
   }
   //returns number of digits
   return numDigits;
}

enum ValidationCode
{
   Ok, // validation passed
   NumDigits, // wrong number of digits
   ExtraChars // extra characters in isbn
};

//function to validate isbn
enum ValidationCode validate(string &isbn)
{
   //calling normalize function
   string normal = normalize(isbn);
  
   //calling numDigits
   size_t count = numDigits(normal);
  
   //if count less not equal to 10
   if (count != 10)
   {
       //returns NumDigits
       return NumDigits;
   }
   //if size of the string is 10 or (size of the string is 11 and last character is X)
   if (normal.size() == 10 || normal.size() == 11 && normal[10] == 'X')
   {
       //returns Ok
       return Ok;
   }
   //returns ExtraChars
   return ExtraChars;
}

int main()
{
   ifstream file;
   string str;
  
   //opening file isbn_data.txt
   file.open("isbn_data.txt");
  
   //loop to read isbn from file and validate
   //file >> str will read each isbn in the file isbn_data
   //this loop will repeat until end of file
   while (file >> str)
   {
       //calling validate function through switch
       switch (validate(str))
       {
           //if validate is Ok
           case Ok:
               cout << str << " is a valid isbn\n";
               break;
          
           //if validate is NumDigits
           case NumDigits:
               cout << str << " doesn't have 10 digits\n";
               break;
          
           //if validate os ExtraChars
           case ExtraChars:
               cout << str << " has extra characters\n";
               break;
          
           //Error condition
           default:
               cout << "ERROR: validate(" << str << ") return an unknown status\n";
               break;
       }

   }
}

OUTPUT

CODE SCREEN SHOT