Suggestions for the Assignment #3:
Problem 1
A function that prints a string of characters in standard set notation should produce the output {b,c,d,a} for the string "bcda". Probably it is good idea to print characters in the ascending order {a,b,c,d}. First, you need to check whether a set is valid ("abc" is valid, but "bcca" is not). Function EMPTY should check whether a string contains at least one character (""={} is empty, but "a"={a} is not) and return 1 if it is empty and zero otherwise (or vice versa). Function EQUAL compares two strings ("abc" is equal to "bca" as in standard set notation it is the same set {a,b,c}). UNION returns the union of two strings (UNION("k#c","cfd")={k,#,c,f,d}). SUBSET checks whether one string is subset of another ("Ab"={A,b} is subset of "kAlMb"). MEMBER function should check whether a character is member of a set ('a' is member of "bca" set).

Tutorial 7

Suggestions for the Assignment #3:
Problem 5
You can use pointer to a function to pass trigonometric or polynomial function as an argument for your MAX() function: float MAX(float (*f_trig)(float), int n, int m, ...). Alternatively, you can pass a number (f=1, 2, 3, 4) to the function MAX(int f, int n, int m,...) which denotes a mathematical function you want to use. In this case mathematical function can be implemented as switch() operator (case 1: y=x^3-x; case 2: y=sin(x);...). If pointers to functions were not covered at lectures by now, you can use the second method.