Don't do advanced code more than chapter 6, functions. C++

6.39 (Binary to decimal) Write a function that returns a decimal number from a binary string. The function header is as follows: int bin2Dec (const string& binaryString) For example, binaryString 10001 is 17 (1x 21 + 0 23 + 0 x 2a + 0 x 2 + 1-17). So, bin2Dec("10001") returns 17. Write a test program that prompts the user to enter a binary number as a string and displays its decimal equivalent value