Well here is again, the refactored version.
"The idea is to have a class to calculate quadratic equations.
This second draft still only calculates real roots (leaving aside imaginary
roots).
But thanks to Damien Cassou I think it has a better style.
A QuadraticEquation is a class used to solve Quadratic Equations of the
form: ax^2 + bx + c = 0, where a is not 0.
You can set the coefficients using the following method
setQuadraticCoefficient: linearCoefficient: constant: "
Object subclass: #QuadraticEquation
instanceVariableNames: 'quadraticCoefficient linearCoefficient constant
roots'
classVariableNames: ''
category: 'IS-Math'
"I create accessors (only getters for each term) and then the following
method to set the terms"
QuadraticEquation>>setQuadraticCoefficient: aNumber1 linearCoefficient:
aNumber2 constant: aNumber3
quadraticCoefficient := aNumber1.
linearCoefficient := aNumber2.
constant := aNumber3
QuadraticEquation>>calculateRoots
| checkNegative |
checkNegative := linearCoefficient squared - ( 4 *
quadraticCoefficient *
constant).
checkNegative >= 0
ifFalse: [ Error signal: 'Negative square root']
ifTrue: [ ^ self solveRoots: checkNegative]
QuadraticEquation>>solveRoots: aTerm
| rootA rootB |
roots := OrderedCollection new.
rootA := (linearCoefficient negated + aTerm sqrt) / (2 *
quadraticCoefficient).
rootB := (linearCoefficient negated - aTerm sqrt) / (2 *
quadraticCoefficient).
roots add: rootA; add: rootB.
^ roots
" Example: -3x^2+2x+2=0
an OrderedCollection(-0.5485837703548636 1.2152504370215302)
print(it)
| anEquation |
anEquation := QuadraticEquation new.
anEquation setQuadraticCoefficient: -3 linearCoefficient: 2 constant:
2.
anEquation calculateRoots."
Thanks again
Best,
Nacho
-----
Nacho
Smalltalker apprentice.
Buenos Aires, Argentina.
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