(HexFormatException) Implement the hex2Dec function in Programming Exercise to throw a Hex...

(HexFormatException) Implement the hex2Dec function in Programming Exercise 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.

Programming Exercise

(invalid_argument) Listing gives the hex2Dec(const string& h exString) function that returns a decimal number from a hex string. Implement the hex2Dec func­tion to throw a invalid_argument exception if the string is not a hex string. Write a test program that prompts the user to enter a hex number as a string and display the number in decimal.

LISTING Hex2Dec.cpp