String Declaration 

Defining String Variables:

A string is an array of bytes, usually terminated by a '$' sign.
A string of characters may be defined in three different ways. For instance, the following definitions are equivalent ways of defining a string "abc":

String definitions
	version1 db "abc"		;string constant
	version2 db ‘a’, ‘b’, ‘c’	;character constants
	version3 db 97, 98, 99	;ASCII codes

The first version uses the method of high level languages and simply encloses the string in quotes. This is the preferred method.
The second version defines a string by specifying a list of the character constants that make up the string.
The third version defines a string by specifying a list of the ASCII codes that make up the string We may also combine the above methods to define a string as in the following example:

Combined definitions
	message db "Hello world", 13, 10, ‘$’

In the above definition, the string message contains ‘Hello world’ followed by Return (ASCII 13), Line-feed (ASCII 10) and the ‘$’ character.
This method is very useful if we wish to include control characters (such as Return) in a string. The string is terminated with the ‘$’ character because the DOS 09 for displaying strings expects the string to be terminated by the ‘$’ character.