please solve it before 20 minutes

Given the underneath fragment code that is written in C language, Write down the function with domain and codomain then prove that function is NOT bijective (One to one and Onto) Show ALL Your Works. IT'S NOT ENOUGH to give a counterexample, you have to check both (Surjectivity and Injectivity) void fun intim, inten *m=(*m(n *n=(int)*(pow ('n 2)-4)