다항식 클래스에 대해 만든 몇 가지 메서드에 문제가 있습니다. CheckZero
의 경우 다항식의 계수에 앞에 오는 0이 있는지 확인해야합니다. 존재하는 경우 계수 배열의 크기를 조정해야하지만 아무 것도 반환하지 않아야합니다. 나는 제대로 달릴 수 없다. 차별화 방법에 대해서는 항상 ArrayIndexOutOfBounds
오류가 발생합니다.다항식 클래스의 오류
import java.util.ArrayList;
public class Poly {
private float[] coefficients;
public static void main (String[] args){
float[] fa = {3, 2, 4};
Poly test = new Poly(fa);
}
public Poly() {
coefficients = new float[1];
coefficients[0] = 0;
}
public Poly(int degree) {
coefficients = new float[degree+1];
for (int i = 0; i <= degree; i++)
coefficients[i] = 0;
}
public Poly(float[] a) {
coefficients = new float[a.length];
for (int i = 0; i < a.length; i++)
coefficients[i] = a[i];
}
public int getDegree() {
return coefficients.length-1;
}
public float getCoefficient(int i) {
return coefficients[i];
}
public void setCoefficient(int i, float value) {
coefficients[i] = value;
}
public Poly add(Poly p) {
int n = getDegree();
int m = p.getDegree();
Poly result = new Poly(Poly.max(n, m));
int i;
for (i = 0; i <= Poly.min(n, m); i++)
result.setCoefficient(i, coefficients[i] + p.getCoefficient(i));
if (i <= n) {
//we have to copy the remaining coefficients from this object
for (; i <= n; i++)
result.setCoefficient(i, coefficients[i]);
} else {
// we have to copy the remaining coefficients from p
for (; i <= m; i++)
result.setCoefficient(i, p.getCoefficient(i));
}
return result;
}
public void displayPoly() {
for (int i=0; i < coefficients.length; i++)
System.out.print(" "+coefficients[i]);
System.out.println();
}
private static int max (int n, int m) {
if (n > m)
return n;
return m;
}
private static int min (int n, int m) {
if (n > m)
return m;
return n;
}
public Poly multiplyCon (double c){
int n = getDegree();
Poly results = new Poly(n);
for (int i =0; i <= n; i++){ // can work when multiplying only 1 coefficient
results.setCoefficient(i, (float)(coefficients[i] * c)); // errors ArrayIndexOutOfBounds for setCoefficient
}
return results;
}
public Poly multiplyPoly (Poly p){
int n = getDegree();
int m = p.getDegree();
Poly result = null;
for (int i = 0; i <= n; i++){
Poly tmpResult = p.multiByConstantWithDegree(coefficients[i], i); //Calls new method
if (result == null){
result = tmpResult;
} else {
result = result.add(tmpResult);
}
}
return result;
}
public void checkZero(){
int newDegree = getDegree();
int length = coefficients.length;
float testArray[] = coefficients;
for (int i = coefficients.length-1; i>0; i--){
if (coefficients[i] != 0){
testArray[i] = coefficients[i];
}
}
for (int j = 0; j < testArray.length; j++){
coefficients[j] = testArray[j];
}
}
public Poly differentiate(){
int n = getDegree();
int newPolyDegree = n - 1;
Poly newResult = new Poly();
if (n == 0){
newResult.setCoefficient(0, 0);
}
for (int i =0; i<= n; i++){
newResult.setCoefficient(i, coefficients[i+1] * (i+1));
}
return newResult;
}
public Poly multiByConstantWithDegree(double c, int degree){ //used specifically for multiply poly
int oldPolyDegree = this.getDegree();
int newPolyDegree = oldPolyDegree + degree;
Poly newResult = new Poly(newPolyDegree);
//set all coeff to zero
for (int i = 0; i<= newPolyDegree; i++){
newResult.coefficients[i] = 0;
}
//shift by n degree
for (int j = 0; j <= oldPolyDegree; j++){
newResult.coefficients[j+degree] = coefficients[j] * (float)c;
}
return newResult;
}
}
편집 : whoops. 잘못된 버전을 복사했습니다.
고정
+1 좋은 답변 인 경우, ** testArray ** 및 ** 계수 **가 동일한 메모리를 가리킬 때 복사가 발생한다고 말하면 -1이어야합니다. –
Woops, 그것을 보지 못했습니다. 답변이 수정되었습니다. 좋은 캐치 :) – tskuzzy