Manipulating Strings

These routines broaden your ability to use strings in interesting ways. STRING REVERSAL (#1) prints strings backward in inverse video characters and is limited to the number of elements in array C (here, 31 characters). To increase the number of elements, just increase C up to memory limits. INVERSE GRAPHICS (#2) converts strings up to 10 characters long into inverse video.

   5 DIM C(30)
  10 PRINT "ENTER A STRING"
  20 INPUT A$
  30 PRINT
  40 PRINT "REVERSE OF ";A$;"  IS:"
  50 LET I=0
  60 LET I=I+1
  70 LET C(I)=CODE(A$)
  80 LET A$=TL$(A$)
  90 IF NOT A$="" THEN GO TO 60
 100 FOR N=0 TO I-1
 110 LET K=I-N
 120 PRINT CHR$(C(K));
 130 NEXT N
 140 PRINT
 150 PRINT
 160 FOR N=0 TO I-1
 170 LET K=I-N
 180 PRINT CHR$(C(K)+128);
 190 NEXT N
 200 PRINT
 210 PRINT
 220 PRINT "-END-"
Syntactic Sum:  23666, 4K

Austin Brown, Jr., Golden, CO

NOTE: Do not use “+” in A$.

  10 LET A$="INVERSE GRAPHICS"
 999 REM **INVERSE SUBROUTINE**
1000 LET ZZ=0
1001 LET XX=ZZ+16431
1002 IF PEEK(XX)=1 THEN LIST
1003 POKE XX,128+PEEK(XX)
1004 LET ZZ=ZZ+1
1005 GO TO 1001
Syntactic Sum:  12223, 4K

Peter Herschel, Newtown Square, PA