Thank you!
On Fri, May 28, 2010 at 10:42, PhilDin <[email protected]> wrote:
> Just to clarify a little more, a variable will only be visible in the
> block in which you declare it. So when you go
>
> public static int prduct(int x, int y)
> {
> int mult;
> mult = (x * y);
> return mult;
> }
>
> the mult variable is only visible between the { and } and the caller
> will not be able to it or any other variable inside your function.
> This gives you the freedom to change the variables inside your
> function without introducing changes into the calling code (this is
> called block scoping, not all languages do it but most do).
>
> I usually explain this to people using the following example from
> mathematics:
>
> Let a=1 and b=f(x)
> Question, what is the value of a?
>
> It's not a trick question, the value of course is 1. In a computer
> program though, the answer is not obvious, f() might change the value
> of a.
>
> What is the lesson? The lesson is that when you call a function, it
> should compute some result and return it, it shouldn't compute some
> result and store it in a variable. There will be exceptions to this
> rule; sometimes your function must change a value. When this happens,
> the name of the function should convey the fact that something will
> change, often by calling it setSomething().
>
> Finally, a note about your naming. You have created a function called
> prduct(), most people can figure out that this means product() but why
> not just call it product() anyway. People used to abbreviate function
> names because there were limits to how long your variable and function
> names could be (I still work with some old code which limits variables
> to 10 characters) but today, your variable and function names can be
> as long as you like.
>
> -phil
>
>
>
>
> On May 28, 3:07 am, Luke Vandervort <[email protected]> wrote:
> > Hi guys, hope you don't mind me asking a question! Can anyone tell me why
> > variable mult is not returning to the main method? Everything else works
> > great! Excuse my ignorance I am just learning this! Thanks!
> >
> > public class Numbers
> > {
> >
> > public static void main(String[] args)
> > {
> > int a = 20;
> > int b = 67;
> >
> > mysum(a, b);
> > mydifference(a, b);
> > prduct(a, b);
> >
> > System.out.println("The product of a * b = " + mult);
> > }
> > public static void mysum(int x, int y)
> > {
> >
> > int newsum;
> > newsum = (x + y);
> > System.out.println("The sum of a and b = " + newsum);
> > }
> > public static void mydifference(int x, int y)
> > {
> > int newdifference;
> > newdifference = (x - y);
> > System.out.println("The difference between a and b = " +
> > newdifference);
> > }
> >
> > public static int prduct(int x, int y)
> > {
> > int mult;
> > mult = (x * y);
> > return mult;
> > }
> > }
> >
> > --
> > Luke M. P. Vandervort
> >
> > — Philippians 3:18-19
>
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--
Luke M. P. Vandervort
—Philippians 3:18-19
For many, as I have often told you and now tell you even in tears,
conduct themselves as enemies of the cross of Christ.
Their end is destruction. Their God is their stomach; their glory is in
their "shame." Their minds are occupied with earthly things.
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