CHAPTER 20  

POTPOURRI (MIXED BAG)

  While wrapping up this book, I found there were many concepts and topics that I should have introduced in earlier chapters and I could not fit into a single chapter. These topics are introduced here as a mixed bag with a variety of flavors. Also, I want to congratulate you for getting this far and covering the many chapters. Obviously you have obtained a unique and worthwhile experience. You should be proud and put into use what you have learned. In my own experience, I have found that repetition is the key to my own learning, whether learning a programming language or a natural language like Spanish or even Chinese.  

BIT-WISE OPERATIONS 

One power of C/C++ is the ability to perform low-level operations that are done by machine languages. These operations are performed on bits. Recall, numbers and addresses are represented in binary form internally. In many applications, especially hardware, it is desirable to work with these bits. The language of C/C++ is known as a language that works closely with hardware. Because of the importance of bit-wise operations, C/C++ chooses to use one key strike for bit-wise operators (&, |) and two strikes for the logical operators (&&, ||). The following symbols are used for the C/C++ bit-wise operations.

|           bit-wise or operator

&         bit-wise and operator

^          bit-wise exclusive or operator

<<        shift left operator

>>        shift right operator

~          bit complement (unary operator)   

BIT-WISE OPERATIONS: EXAMPLES 

The general form of the bit-wise or operation is variable1  | variable2 where each variable of type integer is converted to binary (bits). The bit-wise or operation of two bits is zero if both corresponding bits are zero (0), otherwise the resulting bit is one (1). 

The general form of the bit-wise and (&) is variable1 & variable2, where each variable of type integer is converted to binary. The bit-wise and operation of two bits is one if the two corresponding bits have values of 1, otherwise the resulting bit is zero. 

The general form of the bit-wise exclusive or (^) operation is variable1 ^ variable2, where both variables and resulting variable are of type integer and are converted to binary.