problem s programiranjem ulomka

public class ulomek{
	private double stevec;
	private double imenovalec;
	
	public ulomek(){
		this.stevec=1.0;
		this.imenovalec=1.0;
	}
	
	public ulomek(double a, double b){
		this.stevec=a;
		this.imenovalec=b;
	}
	
	public void mnozi(ulomek a, ulomek b){
		this.stevec=a.getstevec()*b.getstevec();
		this.imenovalec =a.getimenovalec()*b.getimenovalec();
	}
	
	public void sestej(ulomek a, ulomek b){
		this.stevec=a.getstevec()*b.getimenovalec()+b.getstevec()*a.getimenovalec();
		this.imenovalec=a.getimenovalec()*b.getimenovalec();
	}
	
	public double getstevec()
	  {
	    return this.stevec;
	  }
	
	public double getimenovalec()
	  {
	    return this.imenovalec;
	  }
	
	 public void setimenovalec(double ime)
	  {
	    this.imenovalec=ime;
	  }
	 
	 public void setistevec(double ime)
	  {
	    this.stevec=ime;
	  }
	
	public String toString() {
		return this.stevec+"/"+this.imenovalec;
	}
}

int main(int argc, char** argv)
{
    ulomek a(2,4);
    ulomek b(1,3);
    ulomek c;
    c = a + b;
    ulomek d;
    d = a * c;
    std::cout << c << std::endl;
    return 0;
}

import java.util.Objects;

public class Ulomek {
  private final int stevec;
  private final int imenovalec;

  public Ulomek(final int stevec, final int imenovalec) {
    if (imenovalec == 0)
      throw new IllegalArgumentException("Imenovalec nesme biti null.");

    final int deljitelj = najvecjiSkupniDeljitelj(stevec, imenovalec);

    this.stevec = stevec / deljitelj;
    this.imenovalec = imenovalec / deljitelj;
  }

  public Ulomek deli(final Ulomek u) {
    return new Ulomek(getStevec() * u.getImenovalec(), getImenovalec() * u.getStevec());
  }

  @Override
  public boolean equals(final Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (!getClass().equals(obj.getClass()))
      return false;

    final Ulomek other = (Ulomek) obj;

    return getStevec() == other.getStevec() && getImenovalec() == other.getImenovalec();
  }

  @Override
  public int hashCode() {
    return Objects.hash(getStevec(), getImenovalec());
  }

  public Ulomek mnozi(final Ulomek u) {
    return new Ulomek(getStevec() * u.getStevec(), getImenovalec() * u.getImenovalec());
  }

  public Ulomek odstej(final Ulomek u) {
    return pristej(new Ulomek(-u.getStevec(), u.getImenovalec()));
  }

  public Ulomek pristej(final Ulomek u) {
    return new Ulomek(getStevec() * u.getImenovalec() + u.getStevec() * getImenovalec(), getImenovalec() * u.getImenovalec());
  }

  @Override
  public String toString() {
    return String.format("%d/%d", getStevec(), getImenovalec());
  }

  private int gcd(final int a, final int b) {
    if (b == 0)
      return a;
    return gcd(b, a % b);
  }

  private int najvecjiSkupniDeljitelj(final int a, final int b) {
    if (a < b)
      return gcd(b, a);
    else
      return gcd(a, b);
  }

  public int getStevec() {
    return stevec;
  }

  public int getImenovalec() {
    return imenovalec;
  }
}