Solved

Code implementing

Posted on 2006-11-20
1
238 Views
Last Modified: 2010-03-31
Hi,

i have the following piece of code but cannot find out what
Pos
Ret
Temp

are asking for me to return can anyone give me any hints?

function LASTAT(s,num)
{       /* XImp  */
var pos in Int
var ret in Int
var temp in Stack of Int
temp <-- s
for (pos <-- 0 to 4)
{
  if (PEEK(temp) == num) then
    {  ret <-- pos  }
  temp <-- POP(temp)
}
return ret
}


Thanks
max
0
Comment
Question by:Max_AJApplegarth
1 Comment
 
LVL 10

Accepted Solution

by:
ADSLMark earned 500 total points
ID: 17981925
It's not Java, but anyway.. it looks like the code takes 4 steps in a stack, comparing the num value with each value on the top of the stack each iteration.
Let's assume we denote a stack with the following notation:
[5, 3, 7, 1] where 5 is the top element.
Let's assume we look at the state at 3 different points namely:

function LASTAT(s,num)
{
    var pos in Int
    var ret in Int
    var temp in Stack of Int
    temp <-- s
>1>>>>>>>>>>>>>>>>>>>>>>>>
    for (pos <-- 0 to 4)
    {
        if (PEEK(temp) == num) then {  ret <-- pos  }
        temp <-- POP(temp)
>2>>>>>>>>>>>>>>>>>>>>>>>>
    }
>3>>>>>>>>>>>>>>>>>>>>>>>>
    return ret
}


Then in an example:
LASTAT([5, 3, 7, 1], 7);

[1] pos=0, ret=0, temp=[5,3,7,1], num=7
[2] pos=0, ret=0, temp=[3,7,1], num=7 (if statement compares PEEK(temp)=5 with num=7)
[2] pos=1, ret=0, temp=[7,1], num=7 (if statement compares PEEK(temp)=3 with num=7)
[2] pos=2, ret=2, temp=[1], num=7 (if statement compares PEEK(temp)=7 with num=7)
[2] pos=3, ret=2, temp=[], num=7 (if statement compares PEEK(temp)=1 with num=7)
[3] pos=3, ret=2, temp=[], num=7 (if statement compares PEEK(temp)=1 with num=7)

I just noticed that the name is LASTAT (=> LastAt). That's what it does, it finds the last index of num in a stack of 4 elements.

pos is used as counter through the stack
ret is used as return value
temp is used as stack copy (since there is a POP, the stack changes so a temporary value is necessary)

I made several assumptions about the language, but i guess this will be sufficient.

Mark
0

Featured Post

Are your AD admin tools letting you down?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
oracle 11g 23 84
java stored proc example 9 32
Java string replace 11 48
Is Applet the way to go for my drag and drop system? 8 17
Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. Java Flight Recorder is a profiling and event collectio…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
Viewers learn how to read error messages and identify possible mistakes that could cause hours of frustration. Coding is as much about debugging your code as it is about writing it. Define Error Message: Line Numbers: Type of Error: Break Down…
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.

831 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question