A string can be created which consists of a series of copies of another string

using STRING$:

10 MODE 135

20 INPUT "What is your string " ,text$

30 copy$=STRING$(10,text$)

40 PRINT "A string containing 10 copies Looks Iike this:"

50 PRINT copy$

INSTR is used to check for the first occurrence of one string within another, for

example:

10 MODE 135

20 INPUT LINE "Ptease type in any sentence",sentence$

30 check=INSTR(sentence$,"e")

40 PRINT "Your sentence contains ";

50 IF check>0 THEN PRINT "an 'e' at position " ;check ELSE PRINT "d

oes not contain an 'e'"

The variable check at line 30 contains the position within sentence$ at which

the first letter e occurs. If sentence$ does not contain an e, check is 0. You can

also search for groups of letters using INSTR. For example replacing line 30

with:

30check=INSTR(sentence$,"the")

makes the program check for the string the within sentence$.

You cannot carry out arithmetic on a string variable, even if that string

variable contains only numeric characters. This can be inconvenient, so there

are two functions which enable you to change a number to a string and vice

versa :

10 MODE 135

20 INPUT "What is today's date (eg 27) ";number

30 number$=STR$(number)

40 INPUT "What month is it ";month$

50date$=month$+" "+number$

60 PRINT "Today's date is ";date$

STR$ in line 30 converts the numeric variable number into a string variable

number$. Lines 50 and 60 are included to demonstrate that the string version

can be concatenated with other strings.

VAL gives the numeric value of a string:

10 MODE 135

20 INPUT "Type in any mixture of numbers and Letters ";mixture$

C 49