string

#string

##Syntax A stringComparison is one of:

(a) stringExpn = stringExpn (b) stringExpn not= stringExpn (c) stringExpn > stringExpn (d) stringExpn < stringExpn (e) stringExpn >= stringExpn (f) stringExpn <= stringExpn

##Description Strings (stringExpns) can be compared for equality (= and not=) and for ordering (>, <, >= and <=).

##Example

    var name : string := "Nancy"
    var licenceNumber : string ( 6 )
    licenceNumber := "175AJN"

##Details Two strings are considered to be equal (=) if they have the same length and are made up, character by character, of the same characters. If they differ, they are considered to be unequal (not=).

Ordering among strings is essentially alphabetic order. String S is considered to come before string T, that is S < T, if the two are identical up to a certain position and after that position, either the next character of S comes before the next character of T, or else there are no more characters in S while T contains more characters.

S > T (S comes after T ) means the same thing as T < S. S >= T means the same thing as S > T or S = T. S <= T means the same thing as S < T or S=T.

ASCII gives the ordering among individual characters. It specifies, among other things, that letter capital L comes alphabetically before capital letter M and similarly for small (lower case) letters.

On IBM mainframe computers, the EBCDIC specification of characters may be used instead of ASCII.