I want to add a number of minutes to a time represented as a String.

Without using any built-in date or time functions, writ a function or method that accepts two

mandatory arguments along with tests to verify functionality. The first argument of the function is

a 12-hour time string with the format "[H]H:MM

{AM|PM}", and the second argument is a signed integer indicating the number of

minutes to add to the time given in the first argument. The return value should be a string of the

same format as the first argument. For example, AddMinutes("9:10 AM", 200) would return

"12:30 PM".

Please provide the explanation for the code also.