Objective (1): Using Stack to match HTML tag in an HTML document, portions of text are delimited
Question:
Objective (1): Using Stack to match HTML tag in an HTML document, portions of text are delimited by HTML tags. A simple opening HTML tag has the form “<name>” and the corresponding Closing tag has the form “</name>”
Example: <body> </body>; <li> </li>
Using java.util.Stack to write a java program to validate the input file html.dat. Display “The input file is a matched HTML document” if there is no mismatch found otherwise display the mismatched tag or any other invalid HTML format.
Objective (2): Using Stack to evaluate post fix expressions Traditionally, arithmetic expressions are written in infix notation, meaning that operator is placed between its operands in the form <operand> <operator> <operand>
In a post fix expression, the operator comes after its two operands. Therefore, a postfix expression takes the form
<operand> <operand> <operator>
For a more complicated example, consider the following infix expression:
(3 * 4 – (2 + 5)) * 4 /2
The equivalent post fix expression is:
34 * 2 5 + - 4 * 2 /
Objective 2
Using java.util.Stack and java.util.StringTokenizer to write a java program to validate and calculate postfix expression from the input data file - postfix.dat (2 points) html.dat:
<body>
<center>
<h1> The Little Boat </h1>
<p>
The storm tossed the little boat like a cheap sneaker in an old washing machine. The three drunken fishermen were used to such treatment, of course, but not the tree salesman, who even as a stowaway now felt that he had overpaid for the voyage.
</p>
<ol><li> Will the salesman die? </li>
<li> What color is the boat? </li>
<li> And what about Naomi? </li>
</ol></body>
postfix.dat:
5 2 + 8 5 - * 2 4 - 5 2 * + 5 2 6 3 - * + 4 + 2 3 1 + * 7 5 0 / 9 3 / 6 / 4 * 10 - 3 / + 9 3 / 6 / 4 * 10 - 5 2 6 3 - * + 4 + 2 3 1 + * 7 - * 9 3 / 6 / 4 * -10 - test.dat: (5+8)-(8*9) ((20*(7-2)5*(6-3) 6*((7-3*2()
/** Source code example for "A Practical Introduction to Data
Structures and Algorithm Analysis, 3rd Edition (Java)"
by Clifford A. Shaffer
Copyright 2008-2011 by Clifford A. Shaffer
*/
/** Stack ADT */
public interface StackLocal<E> {
/** Reinitialize the stack. The user is responsible for
reclaiming the storage used by the stack elements. */
public void clear();
/** Push an element onto the top of the stack.
@param it The element being pushed onto the stack. */
public void push(E it);
/** Remove and return the element at the top of the stack.
@return The element at the top of the stack. */
public E pop();
/** @return A copy of the top element. */
public E topValue();
/** @return The number of elements in the stack. */
public int length();
};
/** A JUnit test class for stacks. */
import java.io.*;
public class StackTokenTest
{
private StackLocal<Character> S1;
private static final char L_PAREN ='(';
private static final char R_PAREN =')';
/**
* This method is automatically called once before each test case method,
* so that all the variables are cleanly initialized for each test.
*/
public void setUp()
{
S1 = new LStack<Character>();
}
public boolean testToken(String s) {
for (int i=0; i < s.length(); i++)
{
if (s.charAt(i) == L_PAREN )
S1.push(L_PAREN);
else
if (s.charAt(i) == R_PAREN )
if (S1.length() == 0) return false;
else
if (S1.pop() != L_PAREN) return false;
}
if (S1.length() !=0)
return false;
else
return true;
}
}
/** A JUnit test class for stacks. */
import java.io.*;
public class StackTokenTest
{
private StackLocal<Character> S1;
private static final char L_PAREN ='(';
private static final char R_PAREN =')';
/**
* This method is automatically called once before each test case method,
* so that all the variables are cleanly initialized for each test.
*/
public void setUp()
{
S1 = new LStack<Character>();
}
public boolean testToken(String s) {
for (int i=0; i < s.length(); i++)
{
if (s.charAt(i) == L_PAREN )
S1.push(L_PAREN);
else
if (s.charAt(i) == R_PAREN )
if (S1.length() == 0) return false;
else
if (S1.pop() != L_PAREN) return false;
}
if (S1.length() !=0)
return false;
else
return true;
}
}
/** Source code example for "A Practical Introduction to Data
Structures and Algorithm Analysis, 3rd Edition (Java)"
by Clifford A. Shaffer
Copyright 2008-2011 by Clifford A. Shaffer
*/
import java.io.*;
public class Lab5TokenTest {
public static void main(String args[]) throws IOException {
char L_br = '(';
char R_br = ')';
File it = new File("test.dat");
LStack<String> in = new LStack<String>();
if (it.exists()) {
FileReader fr = new FileReader(it);
BufferedReader br = new BufferedReader(fr);
String s;
// Build the Stack
in.clear();
System.out.println("List the input records");
StackTokenTest t = new StackTokenTest();
while ((s = br.readLine()) != null){
System.out.println(s);
if(s.length()>0)
in.push(s);
}
br.close();
System.out.println("Print the stack");
System.out.println(in.toString());
while (in.length()>0)
{
System.out.println("Stack size is : "+in.length());
s = in.pop();
t.setUp();
if (t.testToken(s))
System.out.println(s+" is valid ");
else
System.out.println(s+" is invalid");
}
}
else
System.out.println("File named " + args[0] + " does not exist");
}
}
Expert Answer:
Objective 1 This script uses a stack or at least a list in a stacklike manner to find opening HTML tags that arent paired with the corresponding closing tag It does this by going through all the tags ... View the full answer
