Lab 2: Bitwise Operations

Due: Sunday, October 31 at 23:59

Your task is to write a Java program that performs bit operations on integers.

Preliminaries

Click on the assignment link.

Once you have accepted the assignment, you can clone the repository on your computer by following the instruction and begin working.

Be sure to ask any questions on Piazza.

Program specification

In the repository you will find a file named BitDriver.java with some testing code. You create a new file named BitOps.java that countains your code, and make sure that your code compiles and runs correctly with this test code.

In this assignment, you will write a Java class named BitOps with seven different methods, described below. In this assignment, you will only use the Java bit operators & (and), | (or), ^ (xor), >> (right shift), >>> (right shift logical), and << (left shift). You will not receive credit for the assignment if you use addition, subtraction, division, multiplication, or mod/remainder.

You will perform bit operations directly on the integer passed in on the command line, and you are not allowed to convert or change that integer in any way. For any method that asks you to change specific bits, you should assume bits are numbered 31 to 0, with 31 being the most significant bit or highest bit, and 0 being the least signifcant bit or lowest bit. Most of these methods can be written in a single line of code.

For example, say I asked you to write a method named oneIsOne that sets bit one of an integer to one while leaving the rest of the bits unchanged. My code for that method would look like this:

public static int oneIsOne(int x) {
    return x | 2;
}

It may be helpful to know that you can specify the value of an int in hex by prepending it with 0x, e.g., int x = 0xBADBEEF;. You can also specify the value of an int in binary by prepending it with 0b, e.g., int x = 0b0110;.

You will need to write the following methods.

public static int isOdd(int x)
This method returns 1 if x is odd, and 0 if it is even. It returns 0 on 6, and 1 on 5.
public static int divBy4(int x)
This methods performs integer division by 4. It returns 1 on 6, 3 on 13, 0 on 3, and -4 on -16.
public static int nearestOdd(int x)
This method rounds up the number to the nearest odd number. It returns 7 on 6, 5 on 5, and -3 on -4.
public static int flipParity(int x)
This method adds 1 to even numbers, and subtracts one from odd numbers. It returns 7 on 6, 4 on 5, and -4 on -3.
public static int isNegative(int x)
This method returns 0 if x is positive, and 1 if x is negative. It returns 0 on 4, and 1 on -3.
public static int clearBits(int x)
This method sets all bits of x except bits 4 through 7 to 0. It leaves bits 4-7 unchanged. It returns 0 on 3, 128 on 128, 128 on 1668, and 240 on -3.
public static int setBits(int x)
Set bits 4 through 7 of x to 0110. All other bits remain unchanged. It returns 99 on 3, 96 on 128, 1636 on 1668, and -147 on -3.

Submission

Submit the lab by committing your code and pushing it to your GitHub repository.