4. Write a function quality Points that accepts a student grade as a floating point number and returns 4 if it is above 90, 3 if it is above 80, 2 if it is above 70, 1 if it is above 60 and 0 below 60. The main() function should call this function and print out the letter grade A, B, C, D or F using a switch statement. The call should be within a loop that continuously queries for a grade from the keyboard input and exits only when the user enters -1. Objective A review of programming in the Clanguage. Design and run programs in C using - data types, operators, preprocessor directives, variables, scope, control structures (if-then-else, switch, for, while, do-while), arrays, structures, pointers, functions, parameters, pass by value, pass by reference, typedef, memory allocation