/*                                                                           */
/* Now that you have the source file in the editor, let's begin correcting   */
/* the errors in the program.  Use the FIND edit command to locate the er-   */
/* rors beginning at line 70.  Enter F. Enter the string to search for as    */
/* shown below:                                                              */
/*     VALUE = VALUE + CHAR - '0' <ESC>                                      */
/* NOTE: Press A (AGAIN) if the cursor stops at the string definition above. */
/*                                                                           */
$title('===>  Change Maker Demo  <===')

Cmaker: DO;

DECLARE
	TRUE literally '0FFH',
	FALSE literally '0',
	IN_PORT literally '1',
	OUT_PORT literally '2',
	lf_cr (2) BYTE DATA (0AH, 0DH),
	paid_text (*) BYTE DATA (7, 'Paid = '),		
	purchased_text (*) BYTE DATA (8, 'Price = '),		
	coins		WORD,
	change		WORD,
	dollars 	WORD,
	quarters	WORD,
	nickels		WORD,
	dimes		WORD,
	pennies		WORD,
	paid		WORD,
	purchased	WORD;

$eject

	read: PROCEDURE BYTE;  /*Sets char equal to ASCII byte received*/
		DECLARE            /*from port 1; writes byte to output port*/
			char BYTE;     /*also*/

		char = INPUT(in_port);
		RETURN char;
	END read;

	write: PROCEDURE (text_ptr, text_cnt); /*Writes text_cnt ASCII bytes */
		DECLARE                            /*that begin at txt_ptr to port2*/
			text_ptr POINTER,
			text_cnt WORD,
			text BASED text_ptr (1) BYTE,
			i WORD;

		DO i = 0 TO text_cnt - 1;       
			OUTPUT(out_port) = text(i);
		END;
	END write;

	write_decimal: PROCEDURE (value);/*Stores decimal digits in the array*/
		DECLARE                      /*digit_stack; calls for their conver-*/
			value WORD,              /*sion to ASCII*/
			i WORD,
			digit_stack(5) BYTE,
			stk_top WORD;

		stk_top = 5;
		DO WHILE value > 0;
			digit_stack(stk_top := stk_top - 1) = value MOD 10;
			value = value/10;
		END;
		DO i = stk_top TO 5;
/*                                                                           */
/* To fix this error, we will use the Xchange edit command.  Position the    */
/* cursor over the 5 in the string "Do i = stk_top".  Press X to invoke the  */
/* Xchange command.  Now, change the 5 to a 4.  Press <ESC> to terminate     */
/* this command.                                                             */
/* Use the FIND edit command to find the last set of edit instructions. Enter*/
/* F.  Enter the string shown below:                                         */
/*     QUIT <ESC>                                                            */
/* Press A to search beyond the string shown above.                          */
/*                                                                           */
			CALL convert_decimal_digit(digit_stack(i));
		END;
	END write_decimal;

	convert_decimal_digit: PROCEDURE (decimal_digit);/*Converts decimal digit*/
		DECLARE                                      /*to ASCII numbers and  */
			decimal_digit BYTE,                      /*calls WRITE for each  */
				ascii_digit BYTE;                    /*ASCII digit           */

			ascii_digit = decimal_digit + '0';
			CALL write(@ascii_digit, 1);
		END convert_decimal_digit;

	print_coin: PROCEDURE (text_ptr, value); /*Formats writing of change */
		DECLARE                              /*values and TEXT; calls    */
			text_ptr POINTER,                /*Write_decimal procedure   */
			value WORD,
			text BASED text_ptr STRUCTURE (cnt BYTE, string(1) BYTE),
			text_cnt BYTE;

		IF value = 0 THEN
			RETURN;
		CALL write (@('  '), 2);
		CALL write_decimal(value);
		text_cnt = text.cnt;
		IF value = 1 THEN
			text_cnt = text_cnt - 1;		/* make singular */
		CALL write(@text.string, text_cnt);
		CALL write(@lf_cr, 2);
	END print_coin;

	payment: PROCEDURE;                            /*Specifies order in which*/
		DECLARE                                    /*change information is   */
			s_text (*) BYTE DATA (8, ' dollars'),  /*written; calls          */
			q_text (*) BYTE DATA (9, ' quarters'), /*formatting procedure    */
			n_text (*) BYTE DATA (8, ' nickels'),		
			d_text (*) BYTE DATA (6, ' dimes'),		
			p_text (*) BYTE DATA (8, ' pennies'),		
			p1_text (*) BYTE DATA (7, ' penny');		

		IF (dollars OR quarters OR dimes OR nickels OR pennies) = 0 THEN
			CALL write(@('No change'), 9);
		ELSE
			DO;
				CALL write(@('Change = '),9);
				CALL write (@lf_cr, 2);
				CALL print_coin(@s_text,dollars);
				CALL print_coin(@q_text,quarters);
				CALL print_coin(@d_text,dimes);
				CALL print_coin(@n_text,nickels);
				 IF pennies = 1 THEN
				  CALL print_coin(p1_text,pennies);
				 ELSE
				  CALL print_coin(p_text,pennies);
           END;
	END payment;

	get_input: PROCEDURE (text_ptr) WORD;   /*Writes request to output;   */
		DECLARE                             /*converts each received ASCII*/
			text_ptr POINTER,               /*byte to a decimal digit and */
			value_ptr POINTER,              /*assembles decimal values    */
			value WORD,
			char BYTE,
			not_done BYTE,
			text BASED text_ptr STRUCTURE (cnt BYTE, string(1) BYTE);

		CALL write(@text.string, text.cnt);
		value = 0;
		not_done = TRUE;
		DO WHILE not_done;
			char = read;
			IF (char >= '0') AND (char <= '9') THEN
				DO;
					value = value + char - '0';
					value = value / 10;
/*                                                                           */
/* Let's use the REPLACE edit command to fix the errors above.  Use the      */
/* <LEFT-ARROW> key to position the cursor at the beginning of the string    */
/* VALUE = VALUE + CHAR - '0'.  The line should define VALUE as              */
/*     VALUE = VALUE * 10                                                    */
/* You only need to replace to the right of the second VALUE.  Enter R to in-*/
/* voke the REPLACE command.  The editor will prompt you with: REPLACE"".    */
/* Enter the portion of the string you wish to replace as shown below:       */
/*     + CHAR - '0' <ESC>                                                    */
/* When you press the <ESC> key, the editor responds by asking you for the   */
/* string with which to replace + CHAR - '0'.  Enter                         */
/*     * 10 <ESC>                                                            */
/* Now let's replace the string / 10 in the next line of code with the       */
/* string + CHAR - '0'.  Enter R.  The last REPLACE command will be shown.   */
/* Enter the command as shown below (typing over the old REPLACE command):   */
/*     / 10 <ESC> + CHAR - '0' <ESC>                                         */
/* Use the -find edit command to find the last error. Enter - (for -find).   */
/* Enter the string to search for as shown below:                            */
/*     DO I = STK_TOP TO 5 <ESC>                                             */
/*                                                                           */
                END
            ELSE
				not_done = FALSE;
		END;
		RETURN alue;
	END get_input;

begin:;
	DO;
		CALL write (@lf_cr, 2);
		paid = get_input(@paid_text);
		purchased = get_input(@purchased_text);
		CALL write (@lf_cr, 2);
		change = paid - purchased;
		dollars = change/100;
		coins = change MOD 100;
		quarters = coins/25;
		coins = coins MOD 25;
		dimes = coins/10;
		coins = coins MOD 10;
		nickels = coins/5;
		pennies = coins MOD 5;
		IF paid < purchased THEN
			CALL write(@('NO CHEATING!'), 12);
		ELSE
			CALL payment;
	END;
exit:;
	HALT;
END;
/*                                 QUIT                                      */
/* You are now finished with correcting the source errors.  All that remains */
/* is to exit the editor and return to the tutorial.  You can save this      */
/* error free source file or you can exit without saving the file.  If you   */
/* want to save this file, write it to a file other than CMKER2.S2 so that   */
/* you preserve the tutorial file unchanged for future users of the tutorial.*/
/* If you want to save the file, perform the following steps:                */
/*  1.  Enter Q (for QUIT).                                                  */
/*  2.  Enter W (for WRITE).                                                 */
/*  3.  Enter the file name to which you wish to write the edited source     */
/*      code.                                                                */
/*  4.  Press the <ESC> key to terminate the WRITE command.                  */
/*  5.  Enter A (for ABORT) to exit the editor.  NOTE: When the I2ICE prompt */
/*      (*) reappears on the screen, enter N <Enter> to continue with the    */
/*      tutorial.                                                            */
/* If you do not want to save this source file, perform steps 1 and 5 above, */
/* answering "Y" to the request: all changes lost? (y or [n]).               */