package programming.exp;
import acm.program.ConsoleProgram;

public class ComplexMathSolver extends ConsoleProgram {
    @Override
    public void run() {
        HandyInt factor = new HandyInt(5);
        HandyInt exp = new HandyInt(3);

        HandyInt result = multiplyWithPowerOfTwo(factor, exp);

        println(factor + " * 2^" + exp + " = " + result);
    }

    /**
     * Returns the result of multiplying {@code factor} with 2 to the power of
     * {@code exp}.
     *
     * @param factor
     *            the handy integer to multiply with the power.
     * @param exp
     *            the exponent of the power.
     * @return the result of the multiplication.
     */
    private HandyInt multiplyWithPowerOfTwo(HandyInt factor, HandyInt exp) {
        HandyInt one = new HandyInt(1);

        while (exp.getInt() > 0) {
            factor = factor.add(factor);
            exp = exp.sub(one);
        }
        return factor;
    }
}

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package programming.exp;

/**
 * An integer that provides arithmetic operations for great glory.
 */
public class HandyInt {
	/** The integer represented by an instance of this class. */
	private int theInt;

	/**
	 * Constructs a new handy integer representing the given int.
	 *
	 * @param theInt
	 *            the integer to be represented by this instance.
	 */
	public HandyInt(int theInt) {
		this.theInt = theInt;
	}

	/**
	 * Constructs a new handy integer representing the integer represented by
	 * the given handy integer.
	 *
	 * @param handyInt
	 *            the handy integer to intialize the new object with.
	 */
	public HandyInt(HandyInt handyInt) {
		this.theInt = handyInt.theInt;
	}

	/**
	 * Returns the integer represented by this instance.
	 *
	 * @return the represented integer.
	 */
	public int getInt() {
		return theInt;
	}

	/**
	 * Returns a handy integer that represents the sum of this and the other
	 * handy integer.
	 *
	 * @param other
	 *            the handy integer to add.
	 * @return sum of the two handy integers.
	 */
	public HandyInt add(HandyInt other) {
		theInt += other.theInt;
		return this;
	}

	/**
	 * Returns a handy integer that represents the result of subtracting the
	 * other integer from this one.
	 *
	 * @param other
	 *            the handy integer to subtract from this one.
	 * @return difference of the two handy integers.
	 */
	public HandyInt sub(HandyInt other) {
		theInt -= other.theInt;
		return this;
	}

	@Override
	public String toString() {
		return Integer.toString(theInt);
	}
}