/*
 * Eric Liu
 * Mr. Peterson
 * APCS Period 3
 * 15 December 2017
 */

public class Fraction {
	private int denominator;
	private int numerator;
	public Fraction() {
		numerator = 1;
		denominator = 0;
	}
	public Fraction(String input) {
		int slash = 0;
		int neg = 1;
		String blah = "+-";

		if(input.charAt(0) == blah.charAt(0) ||input.charAt(0) == blah.charAt(1)) {
			if(input.charAt(0) == blah.charAt(1)) {
				neg = -1;
			}
			input = input.substring(1);
		}
		for(int i = 0; i <= input.length() - 1; i++) {
			if(input.charAt(i) == '/') {
				break;
			}
			slash++;
		}
		numerator = Integer.parseInt(input.substring(0, slash));
		denominator = Integer.parseInt(input.substring(slash + 1));
		numerator *= neg;

		reduce();
	}
	public Fraction(int num) {
		numerator = num;
		denominator = 1;
	}
	public Fraction(int num, int denom) {
		numerator = (denom < 0 ? -num : num);
		if(denominator == 0) {

		}
		denominator = (denom < 0 ? -denom : denom);
		reduce();
	}
	public void setNumerator(int num) {
		numerator = num;
		reduce();
	}
	public int getNumerator() {
		return numerator;
	}
	public void setDenominator(int denom) {
		if(denom > 0) {
			denominator = denom;
			reduce();
		}
		else if(denom < 0) {
			numerator = -numerator;
			denominator = -denom;
			reduce();
		}
	}
	public int getDenominator() {
		return denominator;
	}

	public Fraction add(Fraction f) {
		f.reduce();
		Fraction sum = new Fraction();
		sum.denominator = denominator * f.denominator;
		sum.numerator =  (numerator * f.denominator + denominator * f.numerator);
		sum.reduce();
		return sum;
	}
	public Fraction subtract(Fraction f) {
		f.reduce();
		Fraction result = new Fraction();
		result.numerator = numerator * f.denominator - f.numerator * denominator;
		result.denominator = denominator * f.denominator;
		result.reduce();
		return result;
	}
	public Fraction multiply(Fraction f) {
		f.reduce();
		Fraction result = new Fraction();
		result.numerator = numerator * f.numerator;
		result.denominator = denominator * f.denominator;
		result.reduce();
		return result;
	}
	public Fraction divide(Fraction f) {
		f.reduce();
		Fraction result = new Fraction();
		if(f.numerator == 0) {
			throw new IllegalArgumentException("Cannot divide by 0");
		}
		result.numerator = numerator * f.denominator;
		result.denominator = denominator * f.numerator;
		result.reduce();
		if(result.denominator < 0 && result.numerator < 0) {
			result.denominator *= -1;
			result.numerator *= -1;
		}
		return result;
	}
	public String toString() {
		if(numerator == 0) {
			return "0";
		}
		else if(denominator == 1) {
			return "" + numerator;
		}
		return numerator + "/" + denominator;
	}
	public String toMixedNumberString() {
		int wholeNum = 0;
		if(numerator > denominator) {
			wholeNum = numerator / denominator;
			numerator -= denominator * wholeNum;
			if(numerator == 0) {
				return "" + wholeNum;
			}
			return "" + wholeNum + "_" + numerator + "/" + denominator;
		}
		else if((numerator*-1) > denominator && numerator < 0) {
			numerator *= -1;
			if(denominator < 0) {
				denominator *= -1;
			}
			wholeNum = numerator / denominator;
			numerator -= denominator * wholeNum;
			if(numerator == 0) {
				return "-" + wholeNum;
			}
			return "-" + wholeNum + "_" + numerator + "/" + denominator;
		}
		return numerator + "/" + denominator;
	}
	public int compareTo(Fraction f) {
		int n = numerator * f.denominator;
		int newn = f.numerator * denominator;
		return n - newn;
	}
	private void reduce() {
		int n = numerator, d = denominator, largest;
		if(numerator < 0) {
			n = -numerator;
		}
		if(n > d) {
			largest = n;
		}
		else {
			largest = d;
		}
		int gcd = 0;
		for(int i = largest; i >= 2; i--) {
			if(numerator % i == 0 && denominator % i == 0) {
				gcd = i;
				break;
			}
		}
		if(gcd != 0) {
			numerator /= gcd;
			denominator /= gcd;
		}
	}
}