cricket 1:13 ... 4G LTE -32% 2 Program 5 [file: gradePts] Need to use file input. Write an interactive C++ program that inputs in a letter grade A/a, B/b, C/C, D/d, or F/f and displays its corresponding grade point value 4, 3, 2, 1, or 0. Must use switch. Enter a letter grade: print: The grade point for Bis 3 Enter a letter grade: T print: Tis an invalid grade