Trying to calculate from file

[mjyz]

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[mjyz]

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[SamuelAdams]

give me a example of your input file.

[Chervil]

Please don't use eof() as the condition in a while loop.
In this case, it leads to loss of data depending upon whether or not there is any whitespace after the last value.

Do this instead:

    while (fin >> num)
    {
        // do stuff with num
    }

As for the specific question, the calculations are not correct.
Look at line 110:

stdDevNumerator += (num-avg) * (num-avg);

And what is the value of avg? Look at line 93:

   total=0, avg = 0;

Aren't you supposed to be using the average obtained from the first pass, in the processing of the second pass?

[mjyz]

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[Chervil]

That version is somewhat worse than the previous version. You still have avg=0; at line 92. That is the cause of the problem.

And to make matters worse, you removed the code
stdDevNumerator += (num-avg) * (num-avg);
from where it belonged, inside the loop, and instead tried to do it afterwards.

I believe the problem you are working on requires the formula:
sqrt( (x₁-m)² + (x₂-m)² + (x₃-m)² + ... + (x_n-m)²) / N )
where m is the mean and N is the number of values.

Here, m must be known before you start, and (x-m)² must be done individually for each value.