Commodore Plus 4 - Page 178

166 Some Programming Techniques
• DEC returns the decimal value of a hexadecimal string.
• DS$ returns the contents of the disk drive error channel (see Appendix A).
• ERRS returns a message that describes an error condition.
• HEX$ returns a hexadecimal text string for a decimal value.
• INSTR finds a string embedded within another string and returns its start
position.
• LEFTS returns the leftmost characters in a string.
• LEN returns the number of characters in a string.
• MIDS returns a character string within another string or replaces a substring in
a character string.
• RIGHTS returns the rightmost characters in a string.
• STR$ converts numeric values into text strings.
• TIS returns the current value of the system clock.
• VAL converts numbers in a string into a numeric value.
Each of these functions is described in Chapter 1. The following sections of this
chapter provide additional information about some of the functions. More
information about ERRS appears under the section about error-trapping
techniques.
When any of these functions contains a text string as a parameter in paren
theses, you can use any of the following forms of text-string representation:
A literal constant text string
A text-string variable
A text-string array variable
A character code in the form CHRS(code)
A concatenation (using +) of any of the above
Any numeric parameter in a string function can be in any of these forms:
A number
A numeric variable
A numeric array variable
A mathematical formula