Write a C++ program using classes and recursion functions to covert a number in a given base (the user enters the base - from 2 to 9) to a decimal number. The algorithm states that each successive...

Extracted text: Write a C++ program using classes and recursion functions to covert a number in a given base (the user enters the base - from 2 to 9) to a decimal number. The algorithm states that each successive digit in the number is multiplied by the base raised to the power corresponding to its position in the number. The low-order digit is in position 0. We sum together all of these products to get the decimal value. For example, in binary- base 2, if we have the binary number 111001, we convert it to decimal as follows: 1x25 + 1x2* + 1x2³ + 0x2²+ 0x2² + 1x2º = 57 For a base 5 number, 14230: 1x5 + 4x53 + 2x52 + 3x5+ Ox5° = 1190 Validate your input. You should check for invalid digits and provide an informative error message to the user. This program requires you to use a recursive function for the conversion to decimal. Failure to do that will result in no points awarded.