Metrologic IS1000 Series Guia do Utilizador descarregar pdf (Página 38)

CipherLab BASIC Compiler

User's Guide

Remarks

If the "condition" is true, loop statements are executed until the WEND statement is

encountered. Then the program execution returns to the WHILE statement and

checks the condition again. If it is still true, the process will be repeated. Otherwise,

the execution continues with the statement following the WEND statement.

Example

WHILE TRANSACTION_COUNT > 0

Data$ = GET_TRANSACTION_DATA$(1)

WRITE_COM(1,Data$)

DEL_TRANSACTION_DATA(1)

WEND

5.4 Commands for String Processing

This section describes BASIC commands used to manipulate sequences of ASCII

characters known as strings. In BASIC, strings are always variable length, from null to a

maximum of 250.

5.4.1 Combining Strings

Two strings can be combined with the plus operator " +". The string following the plus

operator is appended to the string preceding the plus operator. For example,

...

Data$ = DATE$ + TIME$ + EmployeeID$

SAVE_TRANSACTION(Data$)

...

5.4.2 Comparing Strings

Two strings can be compared with the relational operators, see section 4.3.3. A single

character is greater than another character if its ASCII value is greater.

For example, the ASCII value of the letter "B" is greater than the ASCII value of the letter

"A", so the expression "B" > "A" is true.

When comparing two strings, BASIC looks at the ASCII values of corresponding

characters. The first character where the two strings differ determines the alphabetical order

of the strings. For example, the strings "aaabaa" and "aaaaaaaa" are the same up to the

fourth character in each, "b" and "a". Since the ASCII value of "b" is larger than that of "a",

the expression "aaabaa" > "aaaaaaaa" is true.

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Metrologic IS1000 Series Guia do Utilizador Página 38