Read a line of digits and print the largest one.
Input
One line of 1 to 30 digits.
Output
The largest digit in the line.
Examples
Example 1 · Input
3725
Expected output
7
Example 2 · Input
0
Expected output
0
Hints
Hint 1
Keep the largest digit seen so far in a register, starting with '0'.
Hint 2
Read keys until Enter; compare each with the largest so far (characters compare in the same order as the digits).
Hint 3
If the new key is above it, it becomes the largest.
Solution
Show one correct solution (try it yourself first)
; The largest digit
.MODEL SMALL
.STACK 100H
.CODE
MAIN PROC
MOV BL, '0' ; the largest so far
NEXT:
MOV AH, 1
INT 21H
CMP AL, 0DH
JE DONE
CMP AL, BL
JBE NEXT ; not larger
MOV BL, AL
JMP NEXT
DONE:
MOV DL, BL
MOV AH, 2
INT 21H
MOV AH, 4CH
INT 21H
MAIN ENDP
END MAIN