all tests pass

src/Lfraction.java

@@ -63,8 +63,6 @@ public class Lfraction implements Comparable<Lfraction> {
          } else {
             dif = this.de / other.de;
          }
-
-         System.out.println("dif = " + dif);
          return (this.nu*dif) == other.nu;
       }
 
@@ -75,7 +73,37 @@ public class Lfraction implements Comparable<Lfraction> {
     */
    @Override
    public int hashCode() {
-      return 0; // TODO!!!
+      return Objects.hash(this.nu, this.de);
+   }
+
+   /** Reduce the fraction
+    * @return reduced Lfraction
+    */
+   public Lfraction reduce() {
+      long common;
+      if (this.nu == this.de) {
+         common = this.nu;
+      } else {
+         long de1;
+         long de2;
+
+         if (this.nu > this.de) {
+            de1 = this.nu;
+            de2 = this.de;
+         } else {
+            de1 = this.de;
+            de2 = this.nu;
+         }
+
+         long f;
+         while (de2 != 0) {
+            f = de2;
+            de2 = de1 % de2;
+            de1 = f;
+         }
+         common = de1;
+      }
+      return new Lfraction(this.nu / common, this.de / common);
    }
 
    /** Sum of fractions.
@@ -83,7 +111,11 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return this+m
     */
    public Lfraction plus (Lfraction m) {
-      return null; // TODO!!!
+      if (this.de == m.de) {
+         return new Lfraction(this.nu + m.nu, this.de);
+      } else {
+         return new Lfraction((m.nu*this.de)+(this.nu*m.de), (m.de*this.de));
+      }
    }
 
    /** Multiplication of fractions.
@@ -91,7 +123,7 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return this*m
     */
    public Lfraction times (Lfraction m) {
-      return null; // TODO!!!
+      return new Lfraction(this.nu * m.nu, this.de * m.de).reduce();
    }
 
    /** Inverse of the fraction. n/d becomes d/n.
@@ -110,7 +142,7 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return opposite of this fraction: -this
     */
    public Lfraction opposite() {
-      return null; // TODO!!!
+      return new Lfraction(-this.nu, this.de);
    }
 
    /** Difference of fractions.
@@ -118,7 +150,11 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return this-m
     */
    public Lfraction minus (Lfraction m) {
-      return null; // TODO!!!
+      if (this.de == m.de) {
+         return new Lfraction(this.nu - m.nu, this.de);
+      } else {
+         return new Lfraction((this.nu*m.de)-(m.nu*this.de), (m.de*this.de)).reduce();
+      }
    }
 
    /** Quotient of fractions.
@@ -126,7 +162,9 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return this/m
     */
    public Lfraction divideBy (Lfraction m) {
-      return null; // TODO!!!
+      long nu = Math.abs(this.nu * m.de);
+      long de = Math.abs(this.de * m.nu);
+      return new Lfraction(nu, de).reduce();
    }
 
    /** Comparision of fractions.
@@ -135,7 +173,13 @@ public class Lfraction implements Comparable<Lfraction> {
     */
    @Override
    public int compareTo (Lfraction m) {
-      return 0; // TODO!!!
+      if (this.equals(m)) {
+         return 0;
+      } else if (this.nu * m.de  < m.nu * this.de) {
+         return -1;
+      } else {
+         return 1;
+      }
    }
 
    /** Clone of the fraction.
@@ -158,14 +202,18 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return fraction part of this fraction
     */
    public Lfraction fractionPart() {
-      return null; // TODO!!!
+      if (this.nu >= this.de || -this.nu >= this.de) {
+         return new Lfraction(this.nu % this.de, this.de);
+      } else {
+         return new Lfraction(this.nu, this.de);
+      }
    }
 
    /** Approximate value of the fraction.
     * @return numeric value of this fraction
     */
    public double toDouble() {
-      return new Double(this.nu)/this.de;
+      return (double)this.nu/this.de;
    }
 
    /** Double value f presented as a fraction with denominator d > 0.
@@ -174,7 +222,7 @@ public class Lfraction implements Comparable<Lfraction> {
     * @return f as an approximate fraction of form n/d
     */
    public static Lfraction toLfraction (double f, long d) {
-      return null; // TODO!!!
+      return new Lfraction(Math.round(f * d), d);
    }
 
    /** Conversion from string to the fraction. Accepts strings of form