Expression

UM0715

18/24

Doc ID 15798 Rev 2

To add a newline or other control character, use the CHR$() function. Note that CHR$(0) will

prematurely terminate the string. Use the ASCII() function to perform numerical

manipulation on characters.

e.g LET B$ = CHR$( ASCII(B$) + 1) will set B$ to the next letter of

the alphabet.

The ?+? operator will concatenate strings.

10 PRINT ?Fred? + ?Bloggs? + CHR$(42) + x$

Will print FredBloggs* followed by the contents of x$.

Functions with names ending in ?$? always return strings. Parentheses are not optional.

5.3

Relational expressions

Relational expressions are used only in IF ... THEN statements to make conditional jumps.

A relational expression evaluates to either true or false. The allowed operators a =, <>

(doesn’t equal), >, >=, <, <=.

With expressions the comparison is numerical, and with strings it is alphabetical. Both sides

of a relational operator must be of the same type.

Relational expressions can contain the keywords AND and OR. Order of evaluation is left to

right, but parentheses should always be used to disambiguate mixed expressions.

Examples of use:

10 IF (x <= 5 AND x > 0) OR x = 10 THEN 100