plz solve it before 20 min

thank you

Given the underneath fragment code that is written in C language, Write down the function with domain and codomain then prove that function is injective (One to one) but it's not surjective (Onto)? SHOW ALL YOUR WORKS, a counterexample is NOT ENOUGH,_you have to disprove surjectivity and prove injective. void fun(unsigned int *m,unsigned int *n){ unsigned int *z = *m; *m=3*/*m) - 4* (*n); *n=2*(*z) + (*n); }