4. C programming a. Write a subroutine to calculate the remainder of division. Input will be two integers and output will be the remainder of the first input divided by the second input. (3 marks) b. Write a main function to call this subroutine. Input two integers, i.e. 100 and 7, to the subroutine. If the remainder is greater than 4, return 1. Otherwise return 0. The subroutine needs to be placed in a library file. Show what's in the header file and explain how to include the header in the main file. c. Sketch flow charts of the subroutine and the main function. (5 marks) (4 marks)