HP 3000 Manuals HP 3000 Manuals
String Functions
String functions may be used to manipulate string expressions, variables,
or literals. A string expression may consist of a string literal, a
string variable, a string constant, a function result that is a string,
or an expression formed with the concatenation operator.
Note that strings must be initialized just like any other variable. The
string functions and procedures assume that the string parameters contain
valid information. The string functions str, strlen, strltrim, strmax,
strpos, strrpt, or strrtrim, are defined by HP Pascal and are described
on subsequent pages.
str
Usage
str(s, p, e)
Arguments
s A string expression.
p An integer expression indicating the index of the starting
character.
e An integer expression indicating the length of the substring.
Description
The function str(s, p, e) returns the portion of s which starts at s [ p
] and is of length e. The result is type string, and may be used as a
string expression. It is an error if strlen(s) is less than p+ (e-1).
Example
VAR
i: integer;
wish_list: string[132];
granted: string[5];
BEGIN
.
i:= 13;
wish_list:= 'wish1 wish2 wish3 wish4 wish5';
granted:= str(wish_list,i,5); { Selects the 3rd wish. }
{ Granted is 'wish3'. }
END.
strlen
Usage
strlen(s)
Argument
s A string expression.
Description
The function strlen(s) returns the current length of the string or PAC
expression s. If s is not initialized, strlen(s) is undefined.
Example
VAR
ars, vita: string[132];
b: boolean;
BEGIN
.
ars:= 'HELLO';
vita:= 'TO YOU';
IF strlen(ars) > strlen(vita) THEN
b:= true
ELSE
b:=false;
.
writeln (strlen(ars):2,strlen(vita):2);
END.
Output:
5 6
strltrim
Usage
strltrim(s)
Argument
s A string expression.
Description
The function strltrim(s) returns a string consisting of s trimmed of all
leading blanks. The function strrtrim trims trailing blanks.
Example
VAR
s: string[80];
BEGIN
.
s:= ' abc';
s:=strltrim(s); {s is now 'abc'}
. {strlen(s) = 3 }
END.
strmax
Usage
strmax(s)
Argument
s A string variable.
Description
The function strmax(s) returns the maximum length of s. Strmax is useful
for finding the maximum length of VAR string parameters whose maximum is
not determined until run time.
Example
VAR
s: string[15];
BEGIN
s:= ' ABCDE ';
IF strlen(s) = strmax(s) THEN
BEGIN
s:= strltrim(s);
s:= strrtrim(s);
END;
writeln (s,strmax(s):3);
.
END.
Output:
ABCDE 15
strpos
Usage
strpos(s1, s2)
Arguments
s1 A string expression.
s2 A string expression.
Description
The function strpos(s1, s2) returns the integer index of the position of
the first occurrence of s2 in s1. If s2 is not found, zero is returned.
If the length of s2 is zero, the result is 1.
NOTE Some HP Pascal implementations have the order of the two parameters
reversed. Also, your implementation may have a compiler option
that reverses the order of parameters.
Example
CONST
separator = ' ';
VAR
i: integer;
names: string[80];
BEGIN
.
names:= 'Jon Jill Ruth Marnie Bob Joan Wendy';
i:= strpos (names,separator); { i = 4 }
IF i <> 0 THEN
strdelete(names,1,i); { deletes first name }
.
i:= (strpos(names,'Ron')); { i = 0 }
END
strrpt
Usage
strrpt(s, n)
Arguments
s A string expression.
n An integer expression indicating the number of repetitions
where n must be greater than or equal to zero.
Description
The function strrpt(s, n) returns a string composed of s repeated n
times. If n is 0, a zero-length string is returned.
Example
CONST
one = '1';
VAR
b_num: string[12];
BEGIN
.
b_num:= strrpt(one,strmax(b_num)); { b_num is '111111111111' }
b_num:= strrpt ('a',10); { b_num is 'aaaaaaaaaa' }
.
END.
strrtrim
Usage
strrtrim(s)
Argument
s A string expression.
Description
The function strrtrim(s) returns a string consisting of s trimmed of
trailing blanks. Leading blanks are stripped by the function strltrim.
Example
VAR
s: string[80];
BEGIN
.
s:= 'abc ';
.
s:= strrtrim(s); { s is now 'abc' }
. { strlen(s) = 3 }
END.