Return value in an array, Programming Languages

A specification of a function TOARR is given below.


function TOARR(n in Int, s in Stack of Int) return in Array of Int pre n ≥ 0.

post The returned value is an array of size n. It contains items from the stack s, copied in the order in which they appear in s, but with the top item from s in the position with index 1 in the returned array, and so on.

If the stack s contains more than n items, then only the top n items are copied to the returned array.

If the stack s contains fewer than n items, then the returned array is filled up with 0s.

For example, TOARR(6, [1,2,3]) = [3,2,1,0,0,0];

TOARR(4, [1,2,3,4,5]) = [5,4,3,2].

(a) What value is returned by TOARR(n,s) when s is [0,1,2,3,4] and n is 3? [1 mark] (b) The code in XImp below is intended to implement TOARR.

function TOARR(n,s)

{ //XImp

var theArr in Array (of size 4) of Int var index in Int

var temp in Stack of Int temp <-- s

for (index < 1 to n)

{
if (SIZE(s) > 0) then
{
PUT(index,theArr,PEEK(temp))
temp <-- POP(temp)
}
}

return theArr

}

(i) Suppose that the stack s is [0, 1, 2, 3, 4] and n is 3. With these inputs, trace the execution of XImp. Give a trace table showing the values of the variables theArr, index and temp after each execution of the body of the loop.

What value is returned by XImp with these inputs?

(ii) Your trace in part (i) should show that XImp is not a correct implementa- tion of TOARR. By referring to the specification of TOARR, explain why the trace shows the implementation to be incorrect. (Your explanation here does not need to refer to the details of the code in XImp.)

(c) Explain how XImp can be modified to make it correct. ( It is sufficient to give the changes which are needed in order to make the code correct. You do not need to repeat parts of the given code that do not need changing). [6 marks]

(d) Use the WorkPad to test your corrected implementation.

Save the WorkPad file which you use to test your implementation. Include the contents of this file as part of your Solution Document. ( It is sufficient to show t e s t s when s is [0, 1, 2, 3, 4] and n is 3, and for two other suitably chosen input cases.)

Posted Date: 3/7/2013 1:49:25 AM | Location : United States







Related Discussions:- Return value in an array, Assignment Help, Ask Question on Return value in an array, Get Answer, Expert's Help, Return value in an array Discussions

Write discussion on Return value in an array
Your posts are moderated
Related Questions
A partly completed project Cwk 4-students is available for downloading from Studynet Assignments. You are required to amend this BlueJ project to implement a version of the WHEN sy

i what to know how setcapture() api work in c#

The creation of the menu will involve writing procedural code, using decision logic, writing a loop, and using the case statement.  Although it is not required for grading, it is r

Introduction Currently, Omega has 178 stores UK wide. Most cities and large towns within the UK are catered for by Omega. Omega began in 1960's selling various makes of telep

EF308 Assignment 2 Due: 3pm, 26 April 2012 Introduction This assignment is loosely based on Cheung et al. (2005) and Molodtsova and Papell (2009) and examines the out-of- sample pr

**This programming assignment is for use in the LINUX/UNIX environment!! Introduction: System administration often requires custom written programs and tools. One problem a syste

Let the player (denoted U in the diagram below) navigate around the board until she wins the game by finding the exit or is killed by a monster. A player begins the game with a sli

The standard way for debuggers to plant interactive breakpoints in a program in RAM (whatever the processor instruction set) is to save the break pointed instruction and replace it

Hi how can I upload my hw to you experts?

Suppose L is a context-free language and L' is regular. Show that L∩ L' is a context- free language. Specifically, if you're given a PDA diagram of L and a DFA diagram for L' , des