Question

Adapt your Rational class :

public class Rational {

    private int num;
    private int denom;

    public Rational() {
        num = 0;
        denom = 1;
    }

    public Rational(int num, int denom) {
        this.num = num;
        this.denom = denom;
    }

    int getNum() {
        return num;
    }

    int getDenom() {
        return denom;
    }

    public Rational add(Rational rhs) {
        return new Rational(num * rhs.denom + rhs.num * denom, denom * rhs.denom);
    }

    public Rational subtract(Rational rhs) {
        return new Rational(num * rhs.denom - rhs.num * denom, denom * rhs.denom);
    }

    public Rational multiply(Rational rhs) {
        return new Rational(num * rhs.num, denom * rhs.denom);
    }

    public Rational divide(Rational rhs) {
        return new Rational(num * rhs.denom, rhs.num * denom);
    }

    public String toString() {
        return num + "/" + denom;
    }

    public static void main(String[] args) {
        Rational r1 = new Rational(1, 2); // 1/2
        Rational r2 = new Rational(3, 4); // 3/4
        Rational result = new Rational();
        result = r1.add(r2);
        System.out.println(result);
// etc
    }
}

to implement the Comparable interface :

public interface Comparable <T>

int compareTo(T rhs);

}

Answer 1

Hey here is your answer :

public class Rational implements Comparable<Rational>{

private int num;
private int denom;

public Rational() {
num = 0;
denom = 1;
}

public Rational(int num, int denom) {
this.num = num;
this.denom = denom;
}

int getNum() {
return num;
}

int getDenom() {
return denom;
}

public Rational add(Rational rhs) {
return new Rational(num * rhs.denom + rhs.num * denom, denom * rhs.denom);
}

public Rational subtract(Rational rhs) {
return new Rational(num * rhs.denom - rhs.num * denom, denom * rhs.denom);
}

public Rational multiply(Rational rhs) {
return new Rational(num * rhs.num, denom * rhs.denom);
}

public Rational divide(Rational rhs) {
return new Rational(num * rhs.denom, rhs.num * denom);
}

public String toString() {
return num + "/" + denom;
}
  
// compareto method should return a negative integer(usually -1), if the current triggering object is less than the passed one,
// and positive integer (usually +1) if greater than, and 0 if equal.
  
public int compareTo(Rational r){  
   Rational a= this;
   int lhs=a.num * r.num;
   int rhs= a.denom *r.denom;
  
   if(lhs<rhs)return -1;
   if(lhs>rhs)return +1;
   else return 0;
}

public static void main(String[] args) {
Rational r1 = new Rational(1, 2); // 1/2
Rational r2 = new Rational(3, 4); // 3/4
Rational result = new Rational();
result = r1.add(r2);
System.out.println(result);
// etc
}
}