Subroutines changing variables

Question

why does the method on the left not change the value of x? i just can't see why it wouldnt!?!
for the code.....
void dontChange(int z) {              void change(Student s) {
         z = 42;                                s.name = "Fred";
     The lines:                            The lines:
        x = 17;                               stu.name = "Jane";
        dontChange(x);                        change(stu);
        System.out.println(x);                System.out.println(stu.name);
     output the value 17.                  output the value "Fred".
     The value of x is not                 The value of stu is not
     changed by the subroutine,            changed, but stu.name is.
     which is equivalent to                This is equivalent to
        z = x;                                s = stu;
        z = 42;                               s.name = "Fred";

Answer 1

z=x means that the value of x is assigned to the
variable z
z=42 means the the value of 42 is assigned to the
variable z
in order to change x, you have to assign adifferent
value to it like
x=987
this was not done in the code.Becareful of what you say. In the following (slightly
altered code) the output will still be 17.
public static void dontChange(int x) {
x = 42;
public static void main(String[] args) {
int x = 17;
dontChange(x);
System.out.println(x);
be careful of what you say, in the method dontChange(int x)
x is a method variable and it's scope is the method.
please test it