Task 1...

src/main/java/school/lemon/changerequest/java/FractionNumber.java

@@ -0,0 +1,117 @@
+package school.lemon.changerequest.java;
+
+//class
+class FractionNumber {
+
+    private int d1;  //dividend
+    private int d2;  //divisor
+
+    //no arguments constructor
+    public FractionNumber(){
+
+    }
+    //constructor d1 and d2
+    public FractionNumber(int d1, int d2) {
+        if(d2 == 0) throw new IllegalArgumentException("Divisor is zero");
+        this.d1 = d1;
+        this.d2 = d2;
+    }
+
+    // divisor = 1
+    public FractionNumber(int d1) {
+        this(d1,1);
+    }
+
+    //tostring
+    public String toString (){
+        return d1 + "/" + d2;
+    }
+
+    // normalized
+    private static int normalized (int d1, int d2) {
+        if(d2 == 0){
+            return d1; }
+        return normalized(d2, d1%d2);
+    }
+
+    public static int gcm(int d1, int d2){
+        if(d2 == 0){ return d1;}
+        return gcm(d2, d1%d2); }
+
+
+    public static String toNormalize(int d1, int d2) {
+        int gcm = gcm(d1, d2);
+        return (d1 / gcm) + "/" + (d2 / gcm);
+    }
+    //get d1
+    public int getDividend() {
+        return this.d1;
+    }
+    //get d2
+    public int getDivisor() {
+        return this.d2;
+    }
+
+
+    //decimal value
+    public double decimalValue() {
+        return ((double) d1)/((double) d2);
+    }
+
+
+    public String addFraction(FractionNumber otherFraction) {
+        // a/b + c/d = (ad + cb)/bd
+        int a = this.d1;
+        int b = this.d2;
+        int c = otherFraction.d1;
+        int d = otherFraction.d2;
+        return ((a*d) + (c*b)) + "/" + (b*d);
+    }
+
+    public String subFraction(FractionNumber otherFraction) {
+        // a/b - c/d = (ad - cb)/bd
+        int a = this.d1;
+        int b = this.d2;
+        int c = otherFraction.d1;
+        int d = otherFraction.d2;
+        return ((a*d) - (c*b)) + "/" + (b*d);
+    }
+
+    public String mulFraction(FractionNumber otherFraction) {
+        // a/b * c/d = ac/bd
+        int a = this.d1;
+        int b = this.d2;
+        int c = otherFraction.d1;
+        int d = otherFraction.d2;
+        return (a*c) + "/" + (b*d);
+    }
+
+    public String divFraction(FractionNumber otherFraction) {
+        // (a/b) / (c/d) = ad/bc
+        int a = this.d1;
+        int b = this.d2;
+        int c = otherFraction.d1;
+        int d = otherFraction.d2;
+        return (a*d) + "/" + (b*c);
+    }
+
+    public static final FractionNumber zero = new FractionNumber (0);
+    public static final FractionNumber one = new FractionNumber(1);
+
+
+
+    public static void main(String[] args) {
+        FractionNumber fr1 = new FractionNumber(2, 4);
+        FractionNumber fr2 = new FractionNumber(4,7);
+        System.out.println("Normalized: " + toNormalize(fr1.d1, fr1.d2));
+        System.out.println("To string: " + fr1.toString());
+        System.out.println("Get divident: " + fr1.getDividend());
+        System.out.println("Get divisor :" + fr2.getDivisor());
+        System.out.println("Decimal value: " + fr2.decimalValue());
+        System.out.println("Add: " + fr1.addFraction(fr2));
+        System.out.println("Sub: " + fr1.subFraction(fr2));
+        System.out.println("Mul: " + fr1.mulFraction(fr2));
+        System.out.println("Div: " + fr1.divFraction(fr2));
+
+    }
+}