Answer:
Below is the code for Tape.java. Since it is in the package turing, you have to define it in the beginning.
Tape.java:
package turing;
public class Tape {
private Cell currentCell; // Current cell pointer
public Tape() { //Constructor to create a blank tape with a single cell, which contains a blank space.
Cell newCell = new Cell();
newCell.content = ' ';
newCell.prev = null;
newCell.next = null;
currentCell = newCell;
}
public Cell getCurrentCell() { //The pointer to current cell.
return currentCell;
}
public char getContent() { //The content of current cell.
return currentCell.content;
}
public void setContent(char ch) { //ch The character to be set into the current cell.
currentCell.content = ch;
}
public void moveLeft() { //Moves the current cell one position to the left along the tape.
if (currentCell.prev == null) {
Cell newCell = new Cell();
newCell.content = ' ';
newCell.prev = null;
newCell.next = currentCell;
currentCell.prev = newCell;
}
currentCell = currentCell.prev;
}
public void moveRight() { //Moves the current cell one position to the right along the tape.
if (currentCell.next == null) {
Cell newCell = new Cell();
newCell.content = ' ';
newCell.next = null;
newCell.prev = currentCell;
currentCell.next = newCell;
}
currentCell = currentCell.next;
}
public String getTapeContents() { //Returns a String consisting of the chars from all the cells on the tape.
Cell pointer = currentCell;
while (pointer.prev != null)
pointer = pointer.prev;
String strContent = "";
while (pointer != null) {
strContent += pointer.content;
pointer = pointer.next;
}
strContent = strContent.trim(); //Returns a copy of the string, with leading and trailing whitespace omitted.
return strContent;
}
}
Explanation:
