Java Rational实验室

Question

我似乎不知道我的代码出了什么问题。我注释了减()方法，以查看它是否适用于未还原的分数(我不认为这个方法有效)，对于第一个方法，它确实有效，但是当它达到两位数时，当它达到两位数时，我就不知道为什么它不工作了。

public class Rational implements Comparable<Rational> {
private int numerator, denominator;

public Rational() { numerator = 1; denominator = 1; }
public Rational(int num, int denom) { numerator = num; denominator = denom; }

public void setRational(int num, int denom) { setNumerator(num); setDenominator(denom); }
public void setNumerator(int num) { numerator = num; }
public void setDenominator(int denom) { denominator = denom; }

public int getNumerator() { return numerator; }
public int getDenominator() { return denominator; }

public void reduce() {
    setNumerator(this.numerator / gcd(this.numerator, this.denominator));
    setDenominator(this.denominator / gcd(this.numerator, this.denominator));
}
public int gcd(int num1, int num2) {
    if (num2 == 0) return num1;
    return gcd(num2,num1 % num2);
}

public Object clone() { return new Rational(getNumerator(), getDenominator()); }
public boolean equals(Object obj){ return this.compareTo((Rational)obj) == 0; }

public void add(Rational other) {
    this.setNumerator( (this.getNumerator() * other.denominator ) + ( other.numerator * this.getDenominator() ));
    this.setDenominator( this.getDenominator() * other.denominator );
    //reduce();
}

public void sub(Rational other) {
    numerator = ( this.getNumerator() * other.getDenominator() ) - ( other.getNumerator() * this.getDenominator() );
    denominator = ( this.getDenominator() * other.getDenominator() );
    //reduce();
}

public void mult(Rational other) {
    numerator = ( this.getNumerator() * other.getNumerator() );
    denominator = ( this.getDenominator() * other.getDenominator() );
    //reduce();
}

public void div(Rational other) {
    numerator = (this.getNumerator() * other.getDenominator());
    denominator = (this.getDenominator() * other.getNumerator());
    //reduce();
}

public int compareTo(Rational other) {
    reduce();
    other.reduce();

    if ( this.getDenominator() < other.getDenominator() ) {
        return -1;
    }
    else if ( this.getDenominator() == other.getDenominator() ) {
        if( this.getNumerator() < other.getNumerator() ) {
            return -1;
        }
        else if( this.getNumerator() > other.getNumerator() ) {
            return 1;
        }
        else return 0;
    }
    else return 1;
}

public String toString() {
    return this.numerator + "/" + this.denominator + "\n";

}}

这位是跑步者

import static java.lang.System.out;
public class RationalRunner {
public static void main(String args[]) {
    Rational test = new Rational();
    out.println("test = " + test);
    Rational newOne = new Rational(3, 4);
    out.println("newOne = " + newOne);
    out.println("test.equals(newOne) = " + test.equals(newOne));
    newOne = (Rational) test.clone();
    out.println("\n\nnewOne after test.clone() = " + newOne);
    out.println("test.equals(newOne) = " + test.equals(newOne));

    Rational rOne = new Rational(1, 2);
    Rational rTwo = new Rational(2, 3);
    out.println("1/2.equals(2/3) = " + rOne.equals(rTwo));
    test.setRational(4, 6);
    out.println("2/3.equals(4/6) = " + rTwo.equals(test));

    out.println("\n\nrOne = " + rOne);
    out.println("rTwo = " + rTwo);
    out.println("rOne.compareTo(rTwo) = " + rOne.compareTo(rTwo));
    out.println("rTwo.compareTo(rOne) = " + rTwo.compareTo(rOne));
    rOne.add(rTwo);
    out.println("\n\nrOne.add(rTwo) = " + rOne);
    rOne.setRational(1, 2);
    rTwo.setRational(1, 3);
    rOne.add(rTwo);
    out.println("\n\n1/2.add(1/3) = " + rOne);

    rOne.setRational(4, 10);
    rTwo.setRational(3, 5);
    rOne.add(rTwo);
    out.println("\n\n4/10.add(3/5) = " + rOne);
    rOne.setRational(2, 10);
    rTwo.setRational(3, 6);
    rOne.add(rTwo);
    out.println("\n\n2/10.add(3/6) = " + rOne);
    //1/4 + 2/8 = 1/2
    rOne.setRational(1, 4);
    rTwo.setRational(2, 8);
    out.println("\n\n1/4.equals(2/8) = " + rOne.equals(rTwo));
    rOne.add(rTwo);
    out.println("\n\n1/4.add(2/8) = " + rOne);

    //1/6 + 2/8 = 5/12
    rOne.setRational(1, 6);
    rTwo.setRational(2, 8);
    out.println("\n\n1/6.equals(2/8) = " + rOne.equals(rTwo));
    rOne.add(rTwo);
    out.println("\n\n1/6.add(2/8) = " + rOne);
}

}

Answer 1

例如，当你将其中一个设置为1/6和2/8时，它会产生14/48的值，而应该是20/48。我尝试过重新键入add方法，并尝试了一种不同的方法，但是它仍然出现在14/48中，我不知道为什么

作为您的示例，当我注释掉.equals()方法时，它返回正确的值。因此，我检查您的.compareTo()方法，并发现，您减少了原始数据。经比较，对rOne和rTwo的值进行了修正。

你应该克隆对象并计算它们。

Rational num1 = new Rational(numerator, denominator); Rational num2 = new Rational(other.getNumerator(), other.getDenominator());

我已经改正了：

  public int compareTo(Rational other) {
  //Should create copy constructor
    Rational num1 = new Rational(numerator, denominator);
    Rational num2 = new Rational(other.getNumerator(), other.getDenominator());
    num1.reduce();
    num2.reduce();

    if (num1.getDenominator() < num2.getDenominator()) {
      return -1;
    } else if (num1.getDenominator() == num2.getDenominator()) {
      if (num1.getNumerator() < num2.getNumerator()) {
        return -1;
      } else if (num1.getNumerator() > num2.getNumerator()) {
        return 1;
      } else {
        return 0;
      }
    } else {
      return 1;
    }
  }

P/s:我只是看看你的例子。因此，任何计算器都是错误的，你可以用同样的方式进行修正。