/**
 * APNum class
 * You must use basic ADTs in your implementation.
 * The number of digits in an APnum should only be limited by the availability of memory
 *
 * Don't forget about other classes you need to write.
 * Please make sure your code is readable. Code style will be marked as well as code correctness.
 */

int num;
int x = 0; //Used in APnextdigit

public APnum(){
	this.num=0;
}

private int getNum(APnum n){
       return n.num;
     }

public class APnum {





    /**
     * Adds a digit represented by the character supplied in the second argument as the next
     * least significant digit to the value of the fi rst argument.
     * (Thus, the value of the  first argument is updated.)
     * @param n ADT argument
     * @param c one of the characters '0', '1', '2', '3', '4', '5', '6', '7', '8' or '9'.
     */
    public static void APin(APnum n, char c){
		num = getNum(n)*10 + (Integer.parseInt(Character.toString(c))).intValue();
    }

    /**
     * Takes as its input a reference to an APnum and complements i
     * @param n ADT argument
     */
    public static void APneg(APnum n){
		num = getNum( n) * (-1);
    }

    /**
     * Adds the APnum supplied in the  first argument to the APNumber supplied in the second
     * argument. The value of the  first APNumber is updated with the new value while the value
     * of the second APNumber remains unchanged
     * @param operand1 first ADT argument
     * @param operand2 second ADT argument
     */
    public static void APadd(APnum operand1, APnum operand2){
		num = getNum(operand1) + getNum(operand2);
        // Fill your code in here, required time O(n)
    }

    /**
     * Compares the values of the two APnums supplied as arguments and returns true if
     * they are equal and false otherwise. The values of the supplied APnums must not change
     * @param operand1 first ADT argument
     * @param operand2 second ADT argument
     * @return true if operand1  and operand 2 are equal and false otherwise
     */
    public static boolean APeq(APnum operand1, APnum operand2){
		if (getNum(operand1) == getNum(operand2)){
			return true;
		}
			return false;
    }

    /**
     * Compares the values of the two APnums supplied as arguments and returns true if
     * the first is strictly less than the second and false otherwise. The values of the supplied
     * APnums must not change
     * @param operand1 first ADT argument
     * @param operand2 second ADT argument
     * @return true if first operand is strictly less than the second operand and false otherwise
     */
    public static boolean APless(APnum operand1, APnum operand2){
		if (getNum(operand1) < getNum(operand2)){
			return true;
		}
			return false;
    }

    /**
     *
     * @param n ADT argument
     * @return the most significant digit of the absolute value of its argument if the value is non-zero.
     * Otherwise, returns the blank character ' '
     */
    public static char APfirstdigit(APnum n){
	num=Integer.toString(getNum(n)).charAt(0);
        // Fill your code in here, required time O(1)
    }

    /**
     *
     * @param n ADT argument
     * @return the next most significant digit of the absolute value of its argument if it exists.
     * Otherwise, returns the blank character ' '
     */
    public static char APnextdigit(APnum n){
		if(x < Integer.toString(getNum(n)).length()){
			return Integer.toString(getNum(n)).charAt(x);
		}
			return " ";
}


public class APsystem {
    /**
     * Place for class members
     * (not necessary, depending on implementation there can be members and there can be no members)
     */

    /**
     * Will be invoked at the start of the tests, initializer of APSystem contents.
     * Can be empty if you don't need to initialize anything in APsystem
     * Tests will start according to the following example:
     * APsystem aps = new APsystem();
     * aps.APinit();
     * APnum n = aps.APzero();
     * APnum.APin(n,'1');
     */
    public void APinit(){
        // Fill your code in here
    }
    /**
     *
     * @return a new APNumber with the value 0
     */
    public APnum APzero(){
		APnum n = new APnum();
    }
}