METHODS - Introduction to Java Programming - page 193

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

1234

line#

decimal hex hexValue toHexChar(hexValue)

19 1234 ""

22 2

iteration 1

23 "2" 2

24 77

22 13

iteration 2

23 "D2" D

24 4

22 4

iteration 3

23 "4D2" 4

24 0

The program uses the decimalToHex method (lines 18-28) to convert a decimal integer to a
hex number as a string. The method gets the remainder of the division of the decimal integer
by 16 (line 22). The remainder is converted into a character by invoking the toHexChar
method (line 23). The character is then appended to the hex string (line 23). The hex string is
initially empty (line 19). Divide the decimal number by 16 to remove a hex digit from the
number (line 24). The decimalToHex method repeatedly performs these operations in a loop
until quotient becomes 0 (lines 21-25).
The toHexChar method (lines 31-36) 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 33). 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 . Simi-
larly, if hexValue is between 10 and 15 , it is converted to (char)(hexValue - 10 +
'A') (line 35). For instance, if hexValue is 11 , (char)(hexValue - 10 + 'A') returns B .

5.15

✓ ✓

What is the return value from invoking toHexChar(5) ? What is the return value
from invoking toHexChar(15) ?

Check

Point

5.16

What is the return value from invoking decimalToHex(245) ? What is the return
value from invoking decimalToHex(3245) ?

5.8 Overloading Methods
Overloading methods enables you to define the methods with the same name as long
as their signatures are different.

Key
Point

The max method that was used earlier works only with the int data type. But what if you need to
determine which of two floating-point numbers has the maximum value? The solution is to cre-
ate another method with the same name but different parameters, as shown in the following code:

public static double max( double num1, double num2) {
if (num1 > num2)
return num1;
else
return num2;

}