In this Chapter, you will learn how to handle strings. AMOS Professional Basic has a full range of string manipulation instructions, and experienced Basic programmers should already be familiar with the standard syntax used.
Reading characters in a string
LEFT$
function: return the leftmost characters of a string
destination$=Left$(source$,number)
Left$(destination$,number)=source$
LEFT$ reads the specified number of characters in a source string, starting from the left-hand side, and copies them into a destination string. The first type of usage of this function creates a new destination string from the chosen number of characters of the source string. For example:
E> Do Input "Type in a string:";S$ Print "Display how many characters from" Input "the left?";N Print Left$(S$,N) Loop
The second type of usage replaces the leftmost number of characters in the destination string with the equivalent number of characters from the source string. For example:
E> A$="**** Basic" Left$(A$,4)="AMOS" Print A$
Exactly the same processes can be performed with characters from the right-hand side of a string, by using the equivalent RIGHT$ function.
RIGHT$
function: return the rightmost characters of a string
destination$=Right$(source$,number)
Right$(destination$,number)=source$
Here are two examples demonstrating each version of usage:
E> Print Right$("IGNORED54321",5) A$=Right$("REJECTED0123456789",10) Print A$
E> B$="AMOS ************" Right$(B$,12)="Professsional" Print B$