Java返回方法使用的对象，而不是基对象

10 月 Questions & Answers 83

我试图在Java中重写compareTo方法。出于某种原因，此对象（或基础对象）被覆盖，并与“其他”对象或插入到方法中的对象进行比较

有人知道为什么会这样吗？我不认为我在任何地方凌驾于“这个”之上

测试时，我创建了两个多项式：

多项式1:42，-7,0,5
多项式2:37，-2,0,0,6
预计为42，-7,0,5
“其他”预计为：37、-2、0、0、6
然而，“这个”最终是42，-7,0,5

代码：

public class Polynomial implements Comparable<Polynomial>
{
private static int[] coefficients;

public Polynomial(int[] coefficients){
    if (coefficients.length < 1) {
    this.coefficients = new int[]{0};
    }
    else {
    int current_position = coefficients.length -1;
    while(coefficients[current_position] == 0 && current_position > 0){
        current_position--;
    }
    this.coefficients = new int[current_position +1];
    System.arraycopy(coefficients, 0, this.coefficients, 0, current_position +1);
    System.out.println("this" + this);
}
};

@Override public String toString(){
    StringBuilder sB = new StringBuilder();
    for (int exponents = 0; exponents < coefficients.length; exponents ++){
        if (exponents > 0){
            sB.append (" + ");
        }
    sB.append("(");
    sB.append(Integer.toString(coefficients[exponents]));
    sB.append(")z^");
    sB.append(Integer.toString(exponents));
    }
    return sB.toString();
};

public int getDegree(){
    if(coefficients.length <= 1){
        return 0;
    }
    else {
        return coefficients.length - 1;
    }
};

public int getCoefficient(int k){
    if(k >= coefficients.length)
    {
        return 0;
    }
    else {
        return coefficients[k];
    }
};


public static long evaluate(int x){
    ArrayList<Integer> toSum = new ArrayList<Integer>();
    int summedValue = 0;
    toSum.add(coefficients[0]);
    for (int i = 1; i <= coefficients.length -1; i++){
        int value = x;
        for (int y = 0; y < i -1; y++){
            value = value * x;
        }
        value = value * coefficients[i];
        toSum.add(value);
    }
    summedValue = toSum.stream().mapToInt(value -> value).sum();
    return summedValue;
};

@Override public boolean equals(Object other){
    if (other == this) return true;
    if (other == null) return false;
    if (other.getClass() != this.getClass()) return false;
    Polynomial that = (Polynomial) other;
    if (this.getDegree() != that.getDegree()) return false;
    for (int i = this.getDegree(); i >= 0; i--)
        if (this.coefficients[i] != that.coefficients[i]) return false;
    return true;
};

@Override public int hashCode(){
    return Arrays.hashCode(coefficients);
  };

public int compareTo(Polynomial other){
    System.out.println("this" +  );
    System.out.println("other" + other);
    return 0;
    System.out.println("this " + this.getDegree());
    System.out.println("other " + other.getDegree());
    if (this.getDegree() < other.getDegree()) return -1;
    else if (this.getDegree() > other.getDegree()) return +1;
    else {
        for (int i = coefficients.length - 1; i >= 0; i--) {
    System.out.println("thisC " + this.coefficients[i]);
    System.out.println("otherC " + other.coefficients[i]);
       if (this.coefficients[i] < other.coefficients[i]) return -1;
        if (this.coefficients[i] > other.coefficients[i]) return +1;
    }
    }
    return 0;
};

public static void main(String[] args) {
    int[] c1 = {42, -7, 0, 5};
    int[] c2 = {37, -2, 0, 0, 6};
    Polynomial p1 = new Polynomial(c1);
    System.out.println("p1" + p1);
    Polynomial p2 = new Polynomial(c2);
    System.out.println("p2" + p2);
    System.out.println("compare" + p1.compareTo(p2));

}

  }

Python中文网

有 Java 编程相关的问题?

Java返回方法使用的对象，而不是基对象

共 (1) 个答案

# 1 楼答案