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' This example uses the STATIC statement to preserve the value of a variable
' between calls to the SUB procedure in which the variable is used. The
' program searches for every occurrence of a certain string expression in a
' file and replaces it with another string.
 
' To try this example:
' 1. Choose New Project from the File menu
' 2. Copy the code example below to the code window
' 3. Press F5 to run the example
 
 DECLARE SUB Extension ()
 DECLARE SUB Search ()
 
 CLS                                      ' Clear the screen
 INPUT "Name of file"; F1$
 INPUT "String to replace"; Old$
 INPUT "Replace with"; Nw$
 Rep = 0: Num = 0
 M = LEN(Old$)
 OPEN F1$ FOR INPUT AS #1
 CALL Extension
 OPEN F2$ FOR OUTPUT AS #2
 DO WHILE NOT EOF(1)
     LINE INPUT #1, Temp$
     CALL Search
     PRINT #2, Temp$
 LOOP
 CLOSE
 PRINT "There were "; Rep; " substitutions in "; Num; " lines."
 PRINT "Substitutions are in file "; F2$
 END
 
 STATIC SUB Extension ()
 SHARED F1$, F2$
     Mark = INSTR(F1$, ".")
     IF Mark = 0 THEN
          F2$ = F1$ + ".NEW"
     ELSE
          F2$ = LEFT$(F1$, Mark - 1) + ".NEW"
     END IF
 END SUB
 
 STATIC SUB Search ()
 SHARED Temp$, Old$, Nw$, Rep, Num, M
 STATIC R
     Mark = INSTR(Temp$, Old$)
     WHILE Mark
         Part1$ = LEFT$(Temp$, Mark - 1)
         Part2$ = MID$(Temp$, Mark + M)
         Temp$ = Part1$ + Nw$ + Part2$
         R = R + 1
         Mark = INSTR(Temp$, Old$)
     WEND
     IF Rep = R THEN
          EXIT SUB
     ELSE
          Rep = R
          Num = Num + 1
     END IF
 END SUB