Class Binary3

  • public class Binary3
extends Object
    A class that represents a binary (base-2) number. A binary number is made up of one or more binary digits called bits. A bit has a value that is equal to either 0 or 1. An 8-bit binary number is shown below.

    A Binary number owns the individual bits.

    To convert a binary number to its decimal (base-10) equivalent, each bit is multiplied by an increasing power of 2 starting from the right-most bit. For example, the decimal equivalent of the 8-bit binary number can be calculated as (1 * 128) + (0 * 64) + (0 * 32) + (1 * 16) + (0 * 8) + (1 * 4) + (1 * 2) + (1 * 1) = 151:

    The decimal equivalent of the 3-bit binary number can be calculated as (1 * 4) + (1 * 2) + (1 * 1) = 7:

    • Constructor Summary

      Constructors 
      Constructor Description
      Binary3​(Binary3 other)
      Initializes this binary number by copying the bits from another binary number.
      Binary3​(List<Bit> bits)
      Initializes this binary number to have the specified bits.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean equals​(Object obj)
      Compares this binary number to an object for equality.
      List<Bit> getBits()
      Returns a reference to the list of bits; for testing purposes only.
      Bit getLeftMostBit()
      Returns the left-most bit of this binary number.
      int hashCode()
      Returns a hash code for this binary number.
      static void main​(String[] args)
      A simple test method.
      int numberOfBits()
      Returns the number of bits in this binary number.
      void reverse()
      Reverses the order of the bits of this binary number.
      (package private) static void reverse​(List<Bit> x)
      Using recursion, reverses the order of the elements of the specified list.
      void setBit​(int index, Bit bit)
      Sets a bit at the given index by copying the value of bit into the bit at the given index.
      void shiftRight()
      Shifts all of the bits of this binary number one position to the right.
      int toDecimal()
      Returns the decimal (base 10) value of this binary number as an int value.
      String toString()
      Returns a string representation of this binary number.

    • Constructor Detail

      • Binary3

        public Binary3​(List<Bit> bits)
        Initializes this binary number to have the specified bits. The constructor copies the individual bits into this binary number.
        Parameters:
        bits - the bits of the binary number
        Throws:
        IllegalArgumentException - if bits.size() is less than 1

      • Binary3

        public Binary3​(Binary3 other)
        Initializes this binary number by copying the bits from another binary number.
        Parameters:
        other - the binary number to copy

    • Method Detail

      • numberOfBits

        public int numberOfBits()
        Returns the number of bits in this binary number.
        Returns:
        the number of bits in this binary number

      • getLeftMostBit

        public Bit getLeftMostBit()
        Returns the left-most bit of this binary number. The returned Bit cannot be used to modify this binary number.
        Returns:
        the left-most bit of this binary number

      • setBit

        public void setBit​(int index,
                   Bit bit)
        Sets a bit at the given index by copying the value of bit into the bit at the given index.

        Index 0 is the index of the left-most bit.

        Parameters:
        index - the index of the bit to set
        bit - the value of the bit to set
        Throws:
        IllegalArgumentException - if index is out of bounds for this binary number

      • shiftRight

        public void shiftRight()
        Shifts all of the bits of this binary number one position to the right. The original right-most bit is discarded (that is, it does not wrap around to the left-most bit). The left-most bit is set to 0. For example, if this binary number is:

        110011

        then after shifting the bits right the binary number becomes:

        011001

        This is equivalent to dividing the number by 2 and discarding the remainder.

      • equals

        public boolean equals​(Object obj)
        Compares this binary number to an object for equality. Returns true if and only if obj is a Binary number that represents the same decimal value as this number.

        This method does not use toDecimal to compare the binary numbers. Instead, it makes a copy of the binary number with the fewest number of bits and adds enough zeros to the front of the copied number so that the copied number has the same number of bits as this number; then the binary representation of this number and the copied number are compared for equality. For example if this binary number has the 6-digit representation:

        000011

        and the other binary number has the 3-digit representation:

        011

        then a copy of the shorter number is padded with 3 zeros to become:

        000011

        which has the same binary representation as this number.

        Overrides:
        equals in class Object
        Parameters:
        obj - the object to compare
        Returns:
        true if this binary number is equal to the other binary number, false otherwise

      • reverse

        public void reverse()
        Reverses the order of the bits of this binary number. For example if this binary is:

        010111

        then reversing this binary number changes this binary number to:

        111010

      • reverse

        static void reverse​(List<Bit> x)
        Using recursion, reverses the order of the elements of the specified list. Reversing an empty list causes the method to do nothing (and does not cause an exception to be thrown).
        Parameters:
        x - a list to reverse

      • toDecimal

        public int toDecimal()
        Returns the decimal (base 10) value of this binary number as an int value. If this binary number has 32 bits or more then the user of this method should expect that the result will be incorrect because of overflow.
        Returns:
        the decimal (base 10) value of this binary number

      • toString

        public String toString()
        Returns a string representation of this binary number. The returned string is made up of the bit values (0 or 1) of the number from the left-most bit to the right-most bit.
        Overrides:
        toString in class Object
        Returns:
        a string representation of this binary number

      • hashCode

        public int hashCode()
        Returns a hash code for this binary number.
        Overrides:
        hashCode in class Object
        Returns:
        a hash code for this binary number

      • getBits

        public List<Bit> getBits()
        Returns a reference to the list of bits; for testing purposes only.
        Returns:
        a reference to the list of bits of this binary number

      • main

        public static void main​(String[] args)
        A simple test method.
        Parameters:
        args - not used