rounds numbers????

BlitzPlus Forums/BlitzPlus Beginners Area/rounds numbers????

Paul A. B.

(Posted 2005) [#1]

Hello,
I am currently trying to make a program that uses fractions, such as 1/4, and adds them and subtracts them( i know it sounds stupid, ut i have a special use for it). I dont know how to make fractions, and doubt you can, so i use their decimal equivalents. Anyway, whenever i try to use any type of variable, includng floating point variables, i always get 0 or 1, never .25 or . anything when i didve the two numbers ( like 4 and 1). LIkewise, when i do 10/3, i get 3.0, and never get a decimal. Is there a way to fix this and extend the number of zeros there are after the decimal, or should i learn another programming language for this?

Thanks

GfK	(Posted 2005) [#2]

To get a float result, then at least one of the values in the expression needs to be a float also.

You should also be aware that floats are only single precision in Blitz and therefore not very accurate. So don't rely on 10.0/4 being 0.25. Because it's more likely to be 0.2499999 or something.

Paul A. B.

(Posted 2005) [#3]

Are there any programming languages where the single precisions are extremely accurate?

WolRon

(Posted 2005) [#4]

Why not just keep your fractions AS fractions? In other words, maybe create a 'fraction' type to store your values.

something like this:

Type Fraction
  Field Numerator
  Field Denominator
End Type

WolRon

(Posted 2005) [#5]

Sample code:

Type Fraction
	Field N ;Numerator
	Field D ;Denominator
End Type

a.Fraction = New Fraction
b.Fraction = New Fraction
c.Fraction = New Fraction

a\N = 1: a\D = 4  ;1/4
b\N = 10: b\D = 3 ;10/3

c = Add(a, b)

Print "1/4 + 10/3 = " + c\N + "/" + c\D

a\N = 1: a\D = 11   ;1/11
b\N = 120: b\D = 11 ;120/11

c = Add(a, b)

Print "1/11 + 120/11 = " + c\N + "/" + c\D


WaitKey

Delete Each Fraction
End


Function Add.Fraction(num1.Fraction, num2.Fraction)
	If sum.Fraction = Null Then sum.Fraction = New fraction
	sum\N = num1\N * num2\D + num2\N * num1\D
	sum\D = num1\D * num2\D
	sum = Simplify(sum)
	Return sum
End Function

Function Simplify.Fraction(num.Fraction)
	Repeat
		foundDivisor = False
		For attempt = 1 To 5
			Select attempt
				Case 1
					divisor = 2
				Case 2
					divisor = 3
				Case 3
					divisor = 5
				Case 4
					divisor = 7
				Case 5
					divisor = 11
				;Case 6
					;continue on for as many prime numbers as you want...
			End Select
			If num\N Mod divisor = 0 And num\D Mod divisor = 0
				num\N = num\N / divisor
				num\D = num\D / divisor
				foundDivisor = True
				Exit
			EndIf
		Next
	Until foundDivisor = False
	Return num
End Function

You owe me ;) ...

You know, when I was in sixth grade and was learing how to handle fractions, I thought, OH GOD, this really sucks!

But when I later got into algebra and trigonometry, I realized that using fractions was SO MUCH BETTER than dealing with inaccurate decimals. For instance, a number like 1/3 is perfectly represented as a fraction, but can never be perfectly represented as a decimal. That is when I truly realized how valuable fractions were.

WolRon

(Posted 2005) [#6]

Hey Paul, was the code I submitted of any help to you?