Data commit

Task/Nim-game/ALGOL-68/nim-game.alg

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+BEGIN # play Nim #
+    # gets a single character answer from standin and returns it #
+    PROC answer = ( STRING prompt )CHAR:
+         BEGIN
+             STRING s;
+             INT left := 0;
+             WHILE print( ( prompt, "> " ) );
+                   read( ( s, newline ) );
+                   left      := LWB s;
+                   INT right := UPB s;
+                   WHILE IF left  > right THEN FALSE ELSE s[ left  ] = " " FI DO left  +:= 1 OD;
+                   WHILE IF right < left  THEN FALSE ELSE s[ right ] = " " FI DO right -:= 1 OD;
+                   left /= right
+             DO
+                 print( ( "Please reply with a single character", newline ) )
+             OD;
+             s[ left ]
+         END # answer # ;
+    # play one game #
+    INT    tokens := 12;
+    STRING suffix := "";
+    WHILE
+        CHAR  user;
+        WHILE user := answer( "There are "
+                            + whole( tokens, 0 )
+                            + " tokens"
+                            + suffix
+                            + ", how many do you want to take (1, 2 or 3)"
+                            );
+              user /= "1" AND user /= "2" AND user /= "3"
+        DO
+            print( ( "please answer 1, 2 or 3", newline ) )
+        OD;
+        INT move = ABS user - ABS "0";
+        print( ( "I take ", whole( 4 - move, 0 ), newline ) );
+        suffix  := " left";
+        tokens -:= 4;
+        tokens > 0
+    DO SKIP OD;
+    print( ( "I win!", newline ) )
+END