LOOPS - Introduction to Java Programming: Comprehensive Version - page 183

24 decimal = decimal / 16 ;
25 }
26
27 System.out.println( "The hex number is " + hex);
28 }
29 }

get a hex char

get a letter

Enter a decimal number: 1234
The hex number is 4D2

line#

decimal hex hexValue hexDigit

14 1234 ""

17 2

iteration 1

23 "2" 2

24 77

17 13

iteration 2

23 "D2" D

24 4

17 4

iteration 3

23 "4D2" 4

24 0

The program prompts the user to enter a decimal integer (line 11), converts it to a hex num-
ber as a string (lines 14-25), and displays the result (line 27). To convert a decimal to a hex
number, the program uses a loop to successively divide the decimal number by 16 and obtain
its remainder (line 17). The remainder is converted into a hex character (lines 20-21). The
character is then appended to the hex string (line 23). The hex string is initially empty (line
14). Divide the decimal number by 16 to remove a hex digit from the number (line 24). The
loop ends when the remaining decimal number becomes 0 .
The program converts a hexValue between 0 and 15 into a hex character. If hexValue is
between 0 and 9 , it is converted to (char)(hexValue + '0') (line 21). Recall that when
adding a character with an integer, the character's Unicode is used in the evaluation. For
example, if hexValue is 5 , (char)(hexValue + '0') returns 5 . Similarly, if hexValue
is between 10 and 15 , it is converted to (char)(hexValue - 10 + 'A') (line 21). For
instance, if hexValue is 11 , (char)(hexValue - 10 + 'A') returns B .

5.21

✓ ✓

Will the program work if n1 and n2 are replaced by n1 / 2 and n2 / 2 in line 17
in Listing 5.9?

Check

Point

5.22

In Listing 5.11, why is it wrong if you change the code (char)(hexValue + '0')
to hexValue + '0' in line 21?

5.23

In Listing 5.11, how many times the loop body is executed for a decimal number 245
and how many times the loop body is executed for a decimal number 3245 ?