Help with Visual Basic

[RK]

I'm new to Visual Basic. By trial and error, I keyed in the following code
to determine the price of a Call Option, given stock price, exercise price,
current yield, dividend yield, std. deviation & days to maturity.

Although the function works, I want to create an additional function for Put
Option Price. Many of the same intermediate calculations are used again (eg.
d1, d2, Nd1 and Nd2). How do I code so that I don't have to repeat all this?

Thanks for your help!


Function CallPrice(PS, PE, YTM, DIV, SD, DAYS)
d1 = (Log(PS / PE) + (YTM - DIV + 0.5 * SD ^ 2) * DAYS / 365) / SD /
Sqr(DAYS / 365): d2 = d1 - SD * Sqr(DAYS / 365): Nd1 =
WorksheetFunction.NormSDist(d1): Nd2 = WorksheetFunction.NormSDist(d2):
CallPrice = PS * Nd1 * Exp(-DIV * DAYS / 365) - PE * Nd2 * Exp(-YTM * DAYS /
365)
End Function

 

[Tom Ogilvy]

Say you have 3 basic calculations

Function Calc1(a, b, c)
Calc1 = a + b + c
End function

function Calc2(b,f,g)
calc2 = b + f + g
End Function

Function Calc3(a,f,i)
calc2 = a + f + i
End Function

Now you can use these in any function

Function Master1(a,b,c,d,e,f,g,i)
Master1 = (d + calc1(a,b,c) + calc2(b,f,g))/e + i
End Function

Function Master2(a,b,f,g,i,h)
Master2 = Calc3(a,f,i)/calc2(b,f,g)*h
EndFunction

So as much as you can identify repetative subcalculations, you can use a
construct like the above.