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sammi

Sat Oct 29, 2011 12:45 pm


shifting number in an array

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What is it you are trying to achieve?



What is the problem you are having?



Describe what you have tried to solve this problem



Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)




% Add the value 68 at the start of the filled section
% shifting everything else to the right
% and adjust variables so it will actually print
%
% Example
% Before: 

Please specify what version of Turing you are using



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Insectoid

Sat Oct 29, 2011 1:04 pm


RE:shifting number in an array

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Can only get 2 of the number the move and the rest stay the same

Maybe if you do this often enough, all of them will have moved.


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Tony

Sat Oct 29, 2011 1:52 pm


RE:shifting number in an array

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adding elements to the beginning of an array is incredibly expensive (performance) and complicated (shifting all the other elements). Why would you want to do this?

E.g. you can add the element at the end
[code]
before: [4][3][2][1]
after: [4][3][2][1][68]
[/code]
All the elements preserve the same relative order as in your example, but the insert doesn't require any shifting of elements.


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Beastinonyou

Sat Oct 29, 2011 2:28 pm


Re: shifting number in an array

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However, If you really need to do it like that, you could use something as simple as this:


var nums : flexible array 1 .. 0 of int

for i : 1 .. 4
    new nums, upper (nums) + 1  % Creates new place in array 'nums'
    nums (i) := i %Rand.Int (10, 99), I'm using 'i' to make it appear how you wanted
end for

% Display the original values in array 'nums'
for i : 1 .. upper (nums)
    put "


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sammi

Sat Oct 29, 2011 4:19 pm


RE:shifting number in an array

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now im getting some error message that says "variable has no value" but i declared it above so i dont know what this means


% Add the value 68 at the start of the filled section
% shifting everything else to the right
% and adjust variables so it will actually print
%
% Example
% Before: 


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Insectoid

Sat Oct 29, 2011 4:44 pm


RE:shifting number in an array

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"variable has no value" means you're trying to do something with a variable that has no value yet. When you declare a variable it doesn't yet have a value. 

i? How can I add to i, if I don't know what it is?

i is 0, so we can add to it no problem.

Now, in your code you've created an array of random length between 8 and 14. So 'upper' is at least 8. You then go on to execute a for loop 4 times, filling in the first 4 values in the array and making the array 4 spaces bigger. The array is now between 12 and 18 slots in length. 

Then, you iterate over the entire array and try to output the value at each index in the array. But...we have at least 12 elements, and we only assigned 4 values. That leaves six elements with no value, that you are trying to print. And there, sir, is your error.


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sammi

Sat Oct 29, 2011 4:53 pm


RE:shifting number in an array

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so how would i input that into my code.....????


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Beastinonyou

Sat Oct 29, 2011 5:08 pm


Re: shifting number in an array

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This: 


var nums : flexible array 1 .. numSlots of int


Is your Problem

You're starting your array with an upper bound of 8 to 12. Then later, you're adding 4 more.

You need to start with 0. 


var nums : flexible array 1 .. 0 of int


And also, Why are you printing the array a third time? 


% Print array again
for i : 1 .. numElements
    put "

fix your flexible array bounds, and run it. You'll see what I mean by the output window.


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evildaddy911

Mon Oct 31, 2011 3:07 pm


Re: shifting number in an array

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heres a way that i figures out, you just need to have the computer know what each element is:

var aray : array 1 .. 5 of int

for i : 1 .. 5
    aray (i) := i
end for

for j : 1 .. 5
    put aray (j)
end for
put ""

for decreasing k : 5 .. 2
    aray (k) := aray (k - 1)
    put aray (k)
end for
then you figure out what the new aray(1) is and your all set