I am trying to write an engine simulation program in C++ - please not that I have never done any programming.
I have attached what I have done so far which is a program that calculates the cylinder volume from a crank angle (theta). What I need now to do is use those iterations to find the pressure at each crank angle - the function is in the form of:
P(theta + dtheta) = P(theta) * (V(theta)/V(theta + dtheta))
ie the current pressure is found using the pressure from the previous iteration, the current volume and the previous volume.
How do I write program to use both the current and previous values for volume? Im sure it can be done, I just can't figure out how to do it.
It's 3 am here so I can't offer much assistance for the simple fact that I am having a hard time keeping my eyes open. But here is some food for thought until you get better replies: http://www.daniweb.com/forums/showthread.php?t=1734
Unfortunately I don't have any choice. I'm doing my final year project on engine simulations and I was under the naive impression that I would have a program to use! So now I have to write my own. :lol:
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How do I write program to use both the current and previous values for volume? Im sure it can be done, I just can't figure out how to do it.
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If you only need one previous value, there is a simple answer to your question: Use two volume variables.
It looks like you already have two, i.e. V and V2, but you're only using one of them. I'd rename V2 something more descriptive, like OldV or something, and make it so V has a value before you start the loop. The only addition to the loop would be to add a line at the start that says 'OldV = V;'--then you can do whatever you want with V in the loop body, since you've already stored the previous value. Once you've calculated a new value for V, you can use both the current and previous values as much as you want. OldV will only ever hold the most recent value of V.
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