Question

In C++

(HexFormatException)
Implement the hex2Dec function in Programming Exercise 16.1 to throw a HexFormatException if the string is not a hex string .

Define a custom exception class named HexFormatException. Write a test program that prompts the user to enter a hex number as a string and displays the number in decimal. If the function throws an exception, display "Not a hex number".

Included is the hex2Dec Function

#include <iostream>
#include <string>
#include <cctype>
using namespace std;

// Converts a hex number as a string to decimal
int hex2Dec(const string& hex);

// Converts a hex character to a decimal value
int hexCharToDecimal(char ch);

int main()
{
// Prompt the user to enter a hex number as a string
cout << "Enter a hex number: ";
string hex;
cin >> hex;

cout << "The decimal value for hex number " << hex
<< " is " << hex2Dec(hex) << endl;

return 0;
}

int hex2Dec(const string& hex)
{
int decimalValue = 0;
for (unsigned i = 0; i < hex.size(); i++)
decimalValue = decimalValue * 16 + hexCharToDecimal(hex[i]);

return decimalValue;
}

int hexCharToDecimal(char ch)
{
ch = toupper(ch); // Change it to uppercase
if ('A' <= ch && ch <= 'F')
return 10 + ch - 'A';
else // ch is '0', '1', ..., or '9'
return ch - '0';
}

Answer 1