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tristanbryce7

Wed Oct 10, 2012 3:57 pm


Variable has no value!?

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Hey guys, I have a problem in Turing, I'm new to Turing and just started learning it so yeah. So I made a program that is like a menu, and you have 5 options, and you enter a number for the item you want, and than it asks u how many u want of that , and than calculates the cost.
This is the code for it 
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var food : string (1)
var burgeramount : real
var popamount : real
var friesamount : real
var applepieamount : real
var milkshakeamount : real
var Cost : real


loop
    put "Hello, Please place your order from the following options"
    put "1. Burger = $2.50"
    put "2. Pop = $1.50"
    put "3. Fries = $1.60"
    put "4. Apple Pie = $2.70"
    put "5. Milkshake = $3.15"
    put "6. Done food Selection"
    put ""
    put "Put Item Number Over Here ==>" ..
    getch (food)

    case food of


        label "1" :
            put "How many burgers would you like?"
            get burgeramount
            cls
        label "2" :
            put "How much pop would you like?"
            get popamount
            cls
        label "3" :
            put "How many packs of fries would you like?"
            get friesamount
            cls
        label "4" :
            put "How many Apple Pie would you like?"
            get applepieamount
            cls
        label "5" :
            put "How many milkshakes would you like?"
            get milkshakeamount
            cls
        label "6" :
            cls
            Cost := (2.5 * burgeramount) + (1.5 * popamount) + (1.6 * friesamount) + (2.7 * applepieamount) + (1.5 * milkshakeamount)
            put "The Bill is $", Cost, " !"

        label :
            put "Please put a number from 1-6"
            delay (1500)
            cls

    end case
end loop

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So my problem is , if the person running the program doesnt select all 5 of the items in his selection, it says "variable has no value" . WHich i get, it means since person didn't enter anything for say burger, it wont have anything , so my question is, how do i change the code so that if they dont choose, say, pop and burger, but the other items, the program calculates the cost fine and theres no problem, so how would i change to code to do that ?


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mirhagk

Wed Oct 10, 2012 4:10 pm


RE:Variable has no value!?

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Change

var burgeramount : real 
var popamount : real 
var friesamount : real 
var applepieamount : real 
var milkshakeamount : real 

to
var burgeramount : real :=0
var popamount : real :=0
var friesamount : real :=0
var applepieamount : real :=0 
var milkshakeamount : real :=0

So that they equal 0 by default. That should fix your problem. You need a starting value if you're going to ever use it without it being 100% defined beforehand.

EDIT: For future reference you can use [syntax="turing"] your code here [ / syntax] (but without the spaces) to have the forum use syntax highlighting and put it in a nice code block (like above)


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tristanbryce7

Wed Oct 10, 2012 4:14 pm


Re: Variable has no value!?

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Thank you so muchh!!! Yea, that fixed the problem :), It'll help me a lot in the future too :D

Oh, ok , Sorry, I never knew that lol, my first post on the website, ill try to do it next time


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mirhagk

Wed Oct 10, 2012 7:41 pm


RE:Variable has no value!?

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No problem, welcome to the site. So long as you keep that in mind for your next post we're happy to help.

The code tags will get you help faster because people can look over it quickly and see mistakes. Many people actually skip a question that doesn't have code tags, but I for one look to see if the person is within their first few posts, and will try to help out regardless.

Anyways, if you ever need help just come here, it's a great place to get help, to discuss topics once you get advanced enough and to just converse and ask about university and stuff. Welcome.


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tristanbryce7

Thu Oct 11, 2012 3:55 pm


Re: Variable has no value!?

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Thanks , it means a lot lol , 
yea, once i get into advanced languaging, i could try and converse with the people who know what theyre doing :D