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-rw-r--r--projects/09/List/List.jack46
-rw-r--r--projects/09/List/Main.jack17
2 files changed, 63 insertions, 0 deletions
diff --git a/projects/09/List/List.jack b/projects/09/List/List.jack
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+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/09/List/List.jack
+
+/** Represents a linked list of integers. */
+class List {
+ field int data; // a list consists of a data field,
+ field List next; // followed by a list
+
+ /* Creates a List. */
+ constructor List new(int car, List cdr) {
+ let data = car; // the identifiers car and cdr are used in
+ let next = cdr; // memory of the Lisp programming language
+ return this;
+ }
+
+ /** Accessors. */
+ method int getData() { return data; }
+ method int getNext() { return next; }
+
+ /** Prints this list. */
+ method void print() {
+ var List current; // initializes current to the first item
+ let current = this; // of this list
+ while (~(current = null)) {
+ do Output.printInt(current.getData());
+ do Output.printChar(32); // prints a space
+ let current = current.getNext();
+ }
+ return;
+ }
+
+ /** Disposes this List by recursively disposing its tail. */
+ method void dispose() {
+ if (~(next = null)) {
+ do next.dispose();
+ }
+ // Uses an OS routine to recycle this object.
+ do Memory.deAlloc(this);
+ return;
+ }
+
+ // More list processing methods can come here.
+
+}
diff --git a/projects/09/List/Main.jack b/projects/09/List/Main.jack
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index 0000000..824eb6f
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+++ b/projects/09/List/Main.jack
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+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/09/List/Main.jack
+
+/** Demonstrates the use of the List abstraction. */
+class Main {
+ function void main() {
+ // Creates and uses the list (2,3,5).
+ var List v;
+ let v = List.new(5,null);
+ let v = List.new(2,List.new(3,v));
+ do v.print(); // prints 2 3 5
+ do v.dispose(); // disposes the list
+ return;
+ }
+}