Urgent Help Nedded!!!

galwaydude18

hi,
this is a java related question. i have to repeat this exam in college!!!

int w=6, x=7, y=8, x=9, result;

Compute the following results and show step by step how the result is achieved:

result=w*y/x%z+7;

heres what i got.
result=6*8/7%9+7;
result=48/7%9+7;
result=6%9+7;
result=3+7;
result=10;

is this answer correct

aidan_walsh

No. The operator precedence is correct, but the final answer is incorrent.

fragile

Your mistake is with the modulus operator, here some instructions..

http://www.cs.umd.edu/~clin/MoreJava/Intro/expr-mod.html

aidan_walsh

Whereas I was leaving it open for him to find the answer himself... Like a good programmer should learn to do, rather than have the solution handed on a silver platter.

fragile

doodle_sketch wrote:

Whereas I was leaving it open for him to find the answer himself... Like a good programmer should learn to do, rather than have the solution handed on a silver platter.

I was trying to do the same, but with a thread title Urgent Help Nedded!!!, I thought that a little more help was called for

galwaydude18

fragile,
this makes no sense to me! can you please explain? i keep giong over and over it and i still keep getting 10 for the answer!!!

galwaydude18

Please Can Someone Help Me! I Have To Repeat This Exam Next Week And I Cant Afford To Spend Ages Looking For Answers!

galwaydude18

Please Im In Need Of Some Urgent Help Here!!!!!!!!

aidan_walsh

You ran the Modulus operator the wrong way.

9%6 == 3
6%9 == ?

fragile

Galwaydude in all fairness this is only one potential question in your exam, did you read and understand the explanations in the link I posted? I have already told you that your mistake is with your understanding of how the modulus operator works.....come on you are 90% there, just re-read how the modulus operator works and try to figure it out...


I dont mean to be cruel, if you are still stuck just reply and I will post up a full explanation, but you really should give it another genuine try

galwaydude18

fragile 6%9 give a number less than 1. this cannot be correct according to the instructions in the link you gave me!! (the result is always greater than or equal to 0)

fragile

galwaydude18 wrote:

(the result is always greater than or equal to 0)

So, if the result cant be less than 0 what is the remainder of 6%9? and remember this is not the same as 6/9..

galwaydude18

fragile the remainder would be 0 is this correct because if it is that would mean the answer is 7 right?

fragile

PM sent

galwaydude18

fragile i didnt get your pm!

galwaydude18

fragile how about this

int w=6, x=7, y=8, x=9, result;

result=(w-y)/(x-z)+51%(x+5);

i got result=3; for the answer!

zoro

10 % 2 = 0

Why?
Take 2 from 10 until you can't do it fully any more ...
10 - 2 = 8
8 - 2 = 6
6 - 2 = 4
4 - 2 = 0
2 - 2 = 0
0
--> 10%2=0

11 % 2 = ?
11 - 2 = 9
9 - 2 = 7
7 - 2 = 5
5 - 2 = 3
3 - 2 = 1
1 < 2 so stop here. Your MOD answer is 1 (your remainder)

Try it like this so:
15 % 8 = ?
15 - 8 = 7
7 < 8 so stop
7 == your answer

Does that help you to understand it?
Daniel

galwaydude18

thanks! i understand it now! do you know what this means?

int w=6,x=7,y=8,z=9, result;

result=(x>=y)?x-y:y-x;

i do not understand it!!

fragile

galwaydude18 wrote:

thanks! i understand it now! do you know what this means?

int w=6,x=7,y=8,z=9, result;

result=(x>=y)?x-y:y-x;

i do not understand it!!

PM sent

galwaydude18

fragile how about the pm i sent you? what do they mean??? Thanks for your help so far!!!!

galwaydude18

what do these mean?

int w=6,x=7,y=8,z=9, result;

result=x*((y==8)?100:999);

result=(--x*w++)/z++ - ++y;

i do not understand them!!

here's the answers i got! can someone please explain them in more detail?

result=x*((y==8)?100:999);
result=7*((8==8)?100:999);
result=7*100;
result=700;

Ok, for the next one, if the operator is before the variable (--y) you calculate it straight away, if it is after the variable (x++) you ignore it (it does matter in loops, but not in these examples)

result=(--x*w++)/z++ - ++y;
result=(--7*6++)/9++ - ++8;
result=(36)/9 - 9;
result=4-9;
result=-5;

zoro

galwaydude18 wrote:

int w=6,x=7,y=8,z=9, result;
result=x*((y==8)?100:999);

int w = ...... <-- declaration of variables
how? ::
eg: result = x*(y==8)?100:99;
-->
if(y == 8)
result = x*100;
else
result = x*99;
<--

result=x*((y==8)?100:999);
IF y == 8, THEN result = x* 100, ELSE result = x * 999

result=(--x*w++)/z++ - ++y;
x = x - 1;
result = x * w;
w = w + 1;
result = result / z;
z = z + 1;
y = y + 1;
result = result - y;

Ok, for the next one, if the operator is before the variable (--y) you calculate it straight away, if it is after the variable (x++) you ignore it (it does matter in loops, but not in these examples)

If you come across --y, you calculate it before moving on. If you come across y++, you calculate it immediately after using the variable y as it is at that moment.
eg:
x = 1;
y = 3;

++x + --y + --x + y++ = ??
2 + 2 + 1 + 2 = 7
after the calculation:
x = 2;
y = 3;

Is that any clearer now?

*edit*
galwaydude18: The only reason that you're receiving this level of help is that you're obviously stressed out over your upcoming exam. As a rule, programmers generally don't give out real code when someone asks for help - the fact that you're having difficulty grasping these basic elements of Java, shows that you probably lack a deeper understanding of the language in general ... and that's something that we can't help you with.

Remeber that we won't be at your exam with you, and also that at one time, all of us knew absolutely NOTHING about Java. It takes time to learn and master all of these small things - but when you do you'll find that you'll look back on this thread and thing "Damn ... how did I not know that?!"

Daniel

Hobbes

you could write a small java program and then run each step to see what the output is. Might be easier for you to understand.

JohnnyBravo

doodle_sketch wrote:

Whereas I was leaving it open for him to find the answer himself... Like a good programmer should learn to do, rather than have the solution handed on a silver platter.

Dont over estimate the silver platter way
Best way to learn is have a working example

fragile

DRJava is a very useful tool for anybody trying to get to grips with the Java language.

One of the key distinguishing features of DrJava is its Interactions Pane, which allows you to enter and evaluate Java statements and expressions on the fly. This is remarkably useful for beginning students, who no longer have to learn to write main methods, recompile, and run programs from a command line simply to test how a new class or method behaves. From a teaching standpoint, the Interactions Pane is a very easy way to help students learn to write Java without having to explain the full meaning of syntax like "public static void main", and it also provides an ideal way to perform demonstrations in class. The Interactions Pane can also be used to experiment with your own programs or new libraries, or even to create graphical user interfaces interactively

It can be downloaded here

Hobbes

JohnnyBravo wrote:

Dont over estimate the silver platter way
Best way to learn is have a working example

It is in the short term, but if the person can't explain what something is doing all a working example is going to provide is a cut + paste. This is counter productive for learning.

It is quite clear from what he has posted so far that working examples will mean nothing to him.

galwaydude18

Hobbes wrote:

It is in the short term, but if the person can't explain what something is doing all a working example is going to provide is a cut + paste. This is counter productive for learning.

It is quite clear from what he has posted so far that working examples will mean nothing to him.

Thanks to help of everyone eles i now do understand it!!! i went through other past papers this morning and did them all without any problems!!!!

zoro

Well done galwaydude18 - best of luck in your exams!

galwaydude18

how do you do this? i can not figure it out to save my life! even using my notes is no help to me!!!

Rewrite the following program sgement using a for loop

int x=11, y=14;
while (x<=27)
{
System.out.println ("The value of y-x is:" +y-x);
x+=2;
}

Guys your help would be appreciated on this!!!!

aidan_walsh

Honestly, read the loop structure carefully, disect what each line does and re-work it into the format of a for loop instead, its really a very simple example.

galwaydude18

Dude its simple when you know what your talking about and what it means but I honestly do not know what I do to transform it in to a for loop!!! can you please help me!!! PLEASE???????!!!!