please only use iostream and namespace std and nothing else. please make it as simple as possible in C++

4. (10 points) Write a function called is valid phone number that takes a phone number as an array of characters and its size, and returns true if the input array is a valid phone number, false otherwise. A phone number is valid only if it is of the following format: (uuu) uuu-uuuu where u is from '0', '1', '2, etc. The parentheses, hypen and the space after ')' are necessary. Do not use the string or regex libraries