Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Code implementing

Posted on 2006-11-20
1
Medium Priority
?
271 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 2000 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

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

By the end of 1980s, object oriented programming using languages like C++, Simula69 and ObjectPascal gained momentum. It looked like programmers finally found the perfect language. C++ successfully combined the object oriented principles of Simula w…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
Viewers learn about the third conditional statement “else if” and use it in an example program. Then additional information about conditional statements is provided, covering the topic thoroughly. Viewers learn about the third conditional statement …
Viewers will learn about basic arrays, how to declare them, and how to use them. Introduction and definition: Declare an array and cover the syntax of declaring them: Initialize every index in the created array: Example/Features of a basic arr…
Suggested Courses

782 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