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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.
}
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