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Thread: Java Question :D
 03122010, 04:29 PM #1Member
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Java Question :D
// method in adding Polynomials that will return c = a + b
public Polynomial add(Polynomial b) {
Polynomial a = this;
Polynomial c = new Polynomial(0, Math.max(a.deg, b.deg));
for (int i = 0; i <= a.deg; i++) c.coef[i] += a.coef[i];
for (int i = 0; i <= b.deg; i++) c.coef[i] += b.coef[i];
c.deg = c.degree();
return c;
}
//method in subracting Polynomials that will return c = (a  b)
public Polynomial subtract(Polynomial b) {
Polynomial a = this;
Polynomial c = new Polynomial(0, Math.max(a.deg, b.deg));
for (int i = 0; i <= a.deg; i++) c.coef[i] += a.coef[i];
for (int i = 0; i <= b.deg; i++) c.coef[i] = b.coef[i];
c.deg = c.degree();
return c;
}
//method in Multiplying Polynomails that will return c = (a * b)
public Polynomial multiply(Polynomial b) {
Polynomial a = this;
Polynomial c = new Polynomial(0, a.deg + b.deg);
for (int i = 0; i <= a.deg; i++)
for (int j = 0; j <= b.deg; j++)
c.coef[i+j] += (a.coef[i] * b.coef[j]);
c.deg = c.degree();
return c;
}
Just want to ask whats the purpose of Polynomial a = "this" < why this .
 03122010, 04:34 PM #2Member
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this referrs to the object itself, so it is a binding to operate with that instance of the object and another Polynomial object.
 03122010, 04:39 PM #3Member
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in the source code, why he used "this"?
instead of other.
 in the source code, why he used "this"?
instead of other.
There's no absolute need to use this in the code above if you reference the object's data directly:
Java Code:public Polynomial add(Polynomial b) { //Polynomial a = this; Polynomial c = new Polynomial(0, Math.max(deg, b.deg)); for (int i = 0; i <= deg; i++) c.coef[i] += coef[i]; for (int i = 0; i <= b.deg; i++) c.coef[i] += b.coef[i]; c.deg = c.degree(); return c; }
Oh, please look at my signature below and add edit your posts above to add code tags to your pasted code. It will make reading your posts much easier.
Much luck.
 03122010, 04:46 PM #5
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You could've written, say, the add( ... ) method like this:
Java Code:public Polynomial add(Polynomial b) { Polynomial c = new Polynomial(0, Math.max(deg, b.deg)); for (int i = 0; i <= deg; i++) c.coef[i] += coef[i]; for (int i = 0; i <= b.deg; i++) c.coef[i] += b.coef[i]; c.deg = c.degree(); return c; }
kind regards,
Jos
 03122010, 05:01 PM #6Member
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Thanks Guys :D Got it.
Sorry just new in java.
Thanks Sir Jos & Faburable . :)
*Idk to close this thread. lol *

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