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Setting up counter.

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Join Date: Sep 2008

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IrishUpstart IrishUpstart is offline

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Setting up counter.

Oct 22nd, 2008

So I need to create a set of data points for the function v*t+.5at(squared). The data points need to be every .02 seconds from 0 to 2.0 seconds. How do I set up the counter for that? Also, all of these points need to be wrote to a location so that I can try to graph them. What would be the best way to do that?

Thanks in advance

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Join Date: Jun 2007

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Chaster

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Re: Setting up counter.

Oct 22nd, 2008

You could try a double variable, like this:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
 
    for (float c=0.0;c<2.1;c+=0.02) {
        ...
    }
    
    for (float c=0.0;c<2.1;c+=0.02) {
        ...
    }

Inside that for, you compute the values for your function, then you save these either in an array of type double, or (if you want them to be available later) into a text file.

Last edited by Chaster; Oct 22nd, 2008 at 10:27 am.

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Join Date: Jul 2008

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ArkM

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Re: Setting up counter.

Oct 22nd, 2008

Never use this approach in math calculations: 0.02 is a double type approximation of the real number 0.02 so 100*0.02 != 2.0.
In that case you have 100 intervals (and 101 points):

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
double t;
int i;
 
for (t = 0.0,i = 0; i <= 100; ++i, t = i/50.0) {
   .....
}
double t;
int i;

for (t = 0.0,i = 0; i <= 100; ++i, t = i/50.0) {
   .....
}

In that case you also have a ready-to-use index to place all needed values in arrays (to plot graph etc)...
To avoid time expensive conversions of i var from int type to double type you can add in the loop header auxiliary double "index" variable. As usually, no need in this optimization...