Can anyone give me some ideas on how to find the middle value between 3 numbers.?

Assuming it is always 3 numbers, and what you want is the median value, here is a simple way. Find the maximum then the minimum and the one you didn't pick is the median. :)

Also, if the numbers aren't too far apart, then what you could do
is get the average of the 3 numbers, and find the number that is closest
to the average. This will work long as the number aren't too far apart, like
1,2,100;

for example if the input was 1,2,3 and you know that the median is 2,
but if you found the average, totalSum/totalElement = (3+2+1)/3 = 6/3 = 2, then you see that this also gets the correct answer. Use it at your
own risk.

Here's it is...I can find the min, mid and max...
But the problem is when i enter a Descending values like... a=3,b=2,c=1...
i got wrong output... try it,.,.