Calculating percentage

[salvatore renda]

Hello everybody.

Do we have a FUNCTION in PBCC 6 that calculate the percentage difference between two numbers?

Thanks

[Michael Mattias]

No intrinsic function, but PB has subtraction, division and multiplication.

[Stuart McLachlan]

No built in function, but a simple macro does it:
'

#COMPILE EXE
#DIM ALL
MACRO PCDiff(x,y) = ((y-x)/x)*100
FUNCTION PBMAIN() AS LONG
    LOCAL lDebug AS LONG: TXT.WINDOW EXE.FULL$, 10,10,45,85 TO lDebug
    LOCAL a,b AS LONG
    LOCAL c,d AS DOUBLE
    a = 100: b = 67
    TXT.PRINT "Percentage difference between";a;" and" ; b; "is  " ;PCDiff(a,b); "%"
    c = 90 :d = 123.5
    TXT.PRINT "Percentage difference between";c;" and" ; d; "is  " ;PCDiff(c,d); "%"

'Finalise
    TXT.COLOR = %RGB_BLUE
    TXT.PRINT
    TXT.PRINT "  ....Press any key to exit": TXT.WAITKEY$: TXT.END
END FUNCTION
'

[salvatore renda]

No intrinsic function, but PB has subtraction, division and multiplication.

Most probably we got addition as well

[salvatore renda]

No built in function, but a simple macro does it:
'

#COMPILE EXE
#DIM ALL
MACRO PCDiff(x,y) = ((y-x)/x)*100
FUNCTION PBMAIN() AS LONG
LOCAL lDebug AS LONG: TXT.WINDOW EXE.FULL$, 10,10,45,85 TO lDebug
LOCAL a,b AS LONG
LOCAL c,d AS DOUBLE
a = 100: b = 67
TXT.PRINT "Percentage difference between";a;" and" ; b; "is " ;PCDiff(a,b); "%"
c = 90 :d = 123.5
TXT.PRINT "Percentage difference between";c;" and" ; d; "is " ;PCDiff(c,d); "%"

'Finalise
TXT.COLOR = %RGB_BLUE
TXT.PRINT
TXT.PRINT " ....Press any key to exit": TXT.WAITKEY$: TXT.END
END FUNCTION
'

Thanks Bro!

[Michael Mattias]

Most probably we got addition as well

Yes we do; but you don't need addition to calculate the percentage difference between two numbers.

[Dale Yarker]

exactly

[salvatore renda]

Yes we do; but you don't need addition to calculate the percentage difference between two numbers.

As a matter of fact you are right

Percent = ((Num2/Num1) * 100) - 100

No addition required.

[Dale Yarker]

Percent = ((Num2/Num1) * 100) - 100

??? What is "- 100" for?

See MACRO in post 3 for percentage difference as requested in post 1.

[Stuart McLachlan]

??? What is "- 100" for?

See MACRO in post 3 for percentage difference as requested in post 1.

Just a slightly different way of getting the same result. There are several different ways of ordering the single multiplication, division and subtraction operators.

(y-x)/x*100 = (y/x-1)*100 = y/x*100-100 = 100/x*(y-x) = 100*(y-x)/x = 100*y/x-100

y/x*100-100 (or y*100/x-100) may be marginally more efficient once compiled since it uses two constant values and only one operation on two variables.

[Dale Yarker]

Only if 100 is one of x or y

[Stuart McLachlan]

Only if 100 is one of x or y

Nope. See my final edited version of the above.

x = 2: y = 1
1/2*100 = 50 : 50 - 100 = -50%

x = 2: y = 4
4/2*100 = 200 : 200 - 100 = 100%

x = 2: y = 3
3/2*100 = 150 : 150 - 100 = 50%

[Dale Yarker]

Got X and Y reversed going into calculator. That gave a negative result when Y is greater than X compared to positive from shown code lines.

[Michael Mattias]

As a matter of fact you are right

Please don't tell me this was a surprise!

[Eric Pearson]

> the percentage difference between two numbers?

It depends on exactly what you mean. If X = 100 and Y = 150, then X is 66.7% of Y, but Y is 50% larger than X.

[Rodney Hicks]

The 'percentage difference between two numbers' is always 100% of the difference.
OR
Using Eric's values for X and Y we get the following:
Y-X=50 because 150-100=50
50/Y*100= 33.33%
50/X*100= 50%
Ergo the 'percentage difference between two numbers' in this case is 50%-33.33%=16.67%

I rest my case... or cases, as the case may be.

[Stuart McLachlan]

> the percentage difference between two numbers?
It depends on exactly what you mean. If X = 100 and Y = 150, then X is 66.7% of Y, but Y is 50% larger than X.

The 'percentage difference between two numbers' is always 100% of the difference.
...
Ergo the 'percentage difference between two numbers' in this case is 50%-33.33%=16.67%

I just realised that we've been talking about "percentage change", while the OP asked about "percentage difference" which is not the same thing. - so Rodney is partially correct and the solutions above are incorrect

i.e. The difference between two values divided by the average of the two values. Shown as a percentage.
https://www.mathsisfun.com/percentage-difference.html

My previous solution should have been:
MACRO PCDiff(x,y) = ABS((x-y)/((x+y)/2)*100)

WHere x = 100 and y = 150
(100-150) = -50
(100+150)/2 = 125
Percentage difference is 50/125*100 = 40%

[Rodney Hicks]

Well done, Stuart!

[Stuart McLachlan]

Yes we do; but you don't need addition to calculate the percentage difference between two numbers.

N.B. Percentage difference does require addition!

[Stuart McLachlan]

> the percentage difference between two numbers?
It depends on exactly what you mean. If X = 100 and Y = 150, then X is 66.7% of Y, but Y is 50% larger than X.

Percentage change, which you are calculating is generally taken as the change from an "old" or "first" value to a "second" or "new" value (in this case, the first value is x)
i.e. order of the parameters is important.

https://www.mathsisfun.com/numbers/percentage-change.html