Espresso: A Concentrated Introduction to Java
Summary: In this laboratory, you will explore the binary representation of integers in Java.
Corresponding Reading:
Class Documentation::
Contents
a. Review Binary Representation of Integers in Java.
b. Create a new project for this lab, called Binary,
and package within that project, called username.binary. Note that you should use your own username in place of username.
mkdir /home/username/CSC152/Binary mkdir /home/username/CSC152/Binary/username/ mkdir /home/username/CSC152/Binary/username/numbers
c. Start Eclipse and load this project.
In the lab on numbers, you
discovered that when you added a small value to the largest
int (Integer.MAX_VALUE), you got
a negative number and when you subtracted a small value from the
smallest int (Integer.MIN_VALUE),
you got a positive number.
The reading on binary representation suggests why: Java limits the number of bits with which it represents numbers and uses two's complement notation.
Redo the experiment, printing out the binary representation
of each value. That is, print the binary representation of
Integer.MAX_VALUE, the small integer you added,
the sum of those two values, Integer.MIN_VALUE,
the small integer you subtracted, and the difference of those
two values.
Recall that you can use Integer.toBinaryString(i)
to extract the binary representation of an int.
Write a class, DecimalToBinary, that prompts the
user for two integers in base-ten form, prints their representation
in binary, prints their sum in binary, and prints their difference
in binary.
For example,
Enter an integer: 10 Enter another integer: -3 1010 + 11111111111111111111111111111101 = 111 1010 - 11111111111111111111111111111101 = 1101
Note that you will need to use Integer.parseInt
to convert the input strings to int values.
One disadvantage of the prior output is that it doesn't make it immediately clear how the two added values line up. Write a new version of the class that does vertical addition, giving output something like the following:
Enter an integer: 10
Enter another integer: -3
ADDITION
1010
+ 11111111111111111111111111111101
----------------------------------
111
SUBTRACTION
1010
- 11111111111111111111111111111101
----------------------------------
1101
Note that you can add the leading spaces by a clever
combination of append, substring,
and Integer.numberOfLeadingZeros(i).
Write a program, BitOps, that allows you to explore the
various bitwise operations (&, |,
^, >>, <<).
For example, here's part of the output.
Enter an integer: 10 Enter another integer: 2 BITWISE AND 00000000000000000000000000001010 (10) & 00000000000000000000000000000011 (3) ---------------------------------- 00000000000000000000000000000010 (2) LEFT SHIFT 10 << 3 = 80 00000000000000000000000000001010 << 3 => 00000000000000000000000001010000
Tuesday, 7 February 2006 [Samuel A. Rebelsky]
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