Data commit

Task/Balanced-brackets/XBasic/balanced-brackets.basic

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+' Balanced brackets
+PROGRAM "balancedbrackets"
+VERSION "0.001"
+
+IMPORT "xst"
+
+DECLARE FUNCTION Entry()
+INTERNAL FUNCTION IsStringBalanced(str$)
+INTERNAL FUNCTION Generate$(n%%)
+
+' Pseudo-random number generator
+' Based on the rand, srand functions from Kernighan & Ritchie's book
+' 'The C Programming Language'
+DECLARE FUNCTION Rand()
+DECLARE FUNCTION SRand(seed%%)
+
+FUNCTION Entry()
+  PRINT "Supplied examples"
+  DIM tests$[6]
+  tests$[0] = ""
+  tests$[1] = "[]"
+  tests$[2] = "]["
+  tests$[3] = "[][]"
+  tests$[4] = "][]["
+  tests$[5] = "[[][]]"
+  tests$[6] = "[]][[]"
+  FOR example@@ = 0 TO UBOUND(tests$[])
+    test$ = tests$[example@@]
+    PRINT "The string '"; test$; "' is ";
+    IFT IsStringBalanced(test$) THEN
+      PRINT "OK."
+    ELSE
+      PRINT "not OK."
+    END IF
+  NEXT example@@
+  PRINT
+  PRINT "Random generated examples"
+  XstGetSystemTime (@msec)
+  SRand(INT(msec) MOD 32768)
+  FOR example@@ = 1 TO 10
+    test$ = Generate$(INT(Rand() / 32768.0 * 10.0) + 1)
+    PRINT "The string '"; test$; "' is ";
+    IFT IsStringBalanced(test$) THEN
+      PRINT "OK."
+    ELSE
+      PRINT "not OK."
+    END IF
+  NEXT example@@
+END FUNCTION
+
+FUNCTION IsStringBalanced(s$)
+  paired& = 0
+  i%% = 1
+  DO WHILE i%% <= LEN(s$) && paired& >= 0
+    c$ = MID$(s$, i%%, 1)
+    SELECT CASE c$
+      CASE "[":
+        INC paired&
+      CASE "]":
+        DEC paired&
+    END SELECT
+    INC i%%
+  LOOP
+END FUNCTION (paired& = 0)
+
+FUNCTION Generate$(n%%)
+  opensCount%% = 0
+  closesCount%% = 0
+  ' Choose at random until n%% of one type generated
+  generated$ = ""
+  DO WHILE opensCount%% < n%% && closesCount%% < n%%
+    SELECT CASE (INT(Rand() / 32768.0 * 2.0) + 1)
+      CASE 1:
+        INC opensCount%%
+        generated$ = generated$ + "["
+      CASE 2:
+        INC closesCount%%
+        generated$ = generated$ + "]"
+    END SELECT
+  LOOP
+  ' Now pad with the remaining other brackets
+  IF opensCount%% = n%% THEN
+    generated$ = generated$ + CHR$(']', n%% - closesCount%%)
+  ELSE
+    generated$ = generated$ + CHR$('[', n%% - opensCount%%)
+  END IF
+END FUNCTION generated$
+
+' Return pseudo-random integer on 0..32767
+FUNCTION Rand()
+  #next&& = #next&& * 1103515245 + 12345
+END FUNCTION USHORT(#next&& / 65536) MOD 32768
+
+' Set seed for Rand()
+FUNCTION SRand(seed%%)
+  #next&& = seed%%
+END FUNCTION
+
+END PROGRAM