Some Loose Ends From Chapter 2

• Variable initialization
  • When you declare a variable, you only set asside the memory, you don't initialize it to a value.
  • This is a common source of logic errors.
  • You should always initialize a varaible after you have declared it.
  • C++ allows for autoinitialization of variables.

    	    char anInitial = 'a';
    	    char firstLetter = 'a', secondLetter = 'B';
    	

  • This is a good thing to do.
• Quotations within strings.
  • If you wish to add a quotation (double or single) to a string, you need escape the quote.
  • To do this use the \ character.

    	  string aString = "String with a \"", bstring;
    
    	  bstring = "a string with a \'";
    	

• Constants
  • Constants should be used for any quantity in the program that will not change.
  • They are declared at the top of the program, and have a "global" scope
  • They are preferable to "magic numbers" or number that just show up in the code.
    const float PI = 3.14159; ... area = PI * r * r; area = 3.14159 * r * r;
  • Usually they are in all uppercase.
  • You don't declare variables with the constants. (Slap on the wrist bad)
  • You don't use magic numbers, use constants. (Dirty look bad)
• Block or compound statements
  • Marked with braces
  • A way to make the compiler think multiple statements are in some sense one statement
• Namespaces - don't worry about it, just using namespace std;
• Edit-Compile-Execute cycle