Computer Science Canada

How do you randmomize strings?
Author:  Wintermini [ Fri Jan 08, 2010 9:44 pm ]
Post subject:  How do you randmomize strings?
Basically, I'm doing a MULTIPLE CHOICE quiz with the following questions, and so far i have this down:

Turing:


        var question : array 0 .. 8 of string
        question (0) := "Approximately how big is a serving?"
        question (1) := "What is the recommended serving of Milk and Milk Alternatives for a 15-year-old girl?"
        question (2) := "Eating too much contribute to _____?"
        question (3) := "What is the type of food you shouldn't be eating too much of?"       
        question (4) := "Aside from healthy eating, what else should you do to balance your healthy lifestyle?"       
        question (5) := "Which food products belong in the Grain Products?"
        question (6) := "Which food products belong in the Meat and Meat Alternatives?" 
        question (7) := "Which food products belong in the Fruits and Vegetables?" 

Author:  deltamanx [ Fri Jan 08, 2010 9:56 pm ]
Post subject:  Re: How do you randmomize strings?
You could take the long round about way of doing it and do this:

code:

var something : int

something := randint (0, 7)

if something = 0 then
put question (0)
elsif something = 1 then
put question (1)
elsif ~~~
~~~
~~~
elsif something = 7 then
put question (7)
end if


But I don't think you want to do that.
Author:  Ktomislav [ Sat Jan 09, 2010 11:50 am ]
Post subject:  Re: How do you randmomize strings?
You mean how to make you program asks you a random question?
If so then use what deltamanx said or simplified:

code:
var temp, num_of_q: int
temp := randint (0, num_of_q-1);
put question (temp)


num_of_q is number of questions you have got so far. So for now num_of_q is 8.
The reason -1 is there is because you started your question array from 0.
Hope this helps.
Author:  Insectoid [ Sat Jan 09, 2010 9:17 pm ]
Post subject:  RE:How do you randmomize strings?
The problem with that is that you can have questions repeat. Better to have a 'shuffle' function. There are different ways to do this, the easiest being an array of strings, then select 2 random elements and swap them. Do this X amount of times (I dunno exactly how big X should be, probably array size * another variable. It's hard to judge the point where it can be called 'shuffled').

Shuffling is actually remarkably similar to sorting.
Author:  Ktomislav [ Sun Jan 10, 2010 5:15 am ]
Post subject:  Re: How do you randmomize strings?
If want to make sure your questions don't repeat use array which contains indexes of asked questions.
And ofcourse a counter to know how many questions your program has asked so far.

Lets say asked: array of int and num_asked: int.
So for instance if your program asks question number five num_asked := num_asked + 1;
and asked (num_asked) := 5;

:


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