marco fractions

/* Term 2 Assignment 1 - Fraction */
/* A class which is used to represent fractions*/
public class Fraction
{
  private int numerator;
  private int denominator;

  // write default constructor
  public Fraction(){
    numerator = 1;
    denominator = 1;
  }

  // write constructor for fraction n/d where n, d > 0
  public Fraction(int n, int d){
    if(n > 0){
      numerator = n;
    }
    else{
      numerator = 1;
    }

    if(d > 0){
      denominator = d;
    }
    else{
      denominator = 1;
    }

  }

  // TODO write method to return fraction as a String
  public String toString(){
    return numerator+"/"+denominator;
  }

  // write method to return fraction as a mixed number String
  public String mixedNumber(){
    String toPrint = "";
    int tempInt = 0;
    int tempN = numerator;

    while(tempN >= denominator){
      tempN = tempN - denominator;
      tempInt = tempInt + 1;
    }
    tempN = numerator%denominator;

    if(tempN != 0){
      toPrint = toPrint + tempInt + " " + tempN + "/" + denominator;
    }
    if(tempN == 0){
      toPrint = tempInt + "";
    }
    if(tempN != 0 & tempInt == 0){
      toPrint = tempN + "/" + denominator;
    }
    return toPrint;
  }

  // write method to add fraction n/d to this Fraction
  public void add(int n, int d){
    if(n > 0 & d > 0){
      // a/b and c/d is(a*d + c*b)/(b*d).
      numerator *= d;
      n *= denominator;
      numerator = numerator / (denominator * d);
      denominator = denominator / (denominator * d);
    }
  }
}