Thread: How to print results to screen

Hi! First I want to say that I am a Java beginner and this is my 2nd program.

I created a program that will do a symbol balance test, but I need someone to help me print the results to the screen because I am getting a blank output whenever I try to find a way to do it. I am also reading into a file. Any help is appreciated please.

test.txt looks like {{}}

For ex,

{ { } } = the symbols are equally balanced
{ [ { } = the symbols are not equally balanced

I need someone to help me find a way to print the results like

{{}} are equally balanced
or
{[}} are not equally balanced


I tried using this and placing it near the bottom of the program:

while (!s.empty())
{
System.out.println(s.pop());
 
if (failed == true)
{
System.out.println(" symbols do not match");
}
else
{
System.out.println(" The symbols match");
}

Main Program:

import java.io.* ;
 
public class Stackmain 
{
 
    public Stackmain() 
    {
 
 
 
    }
    public static boolean main(String expression) throws IOException 
    {
 
    final char LEFT_PARENT = '(';
    final char RIGHT_PARENT = ')';
    final char LEFT_CURLY = '{';
    final char RIGHT_CURLY = '}';
    final char LEFT_SQUARE = '[';
    final char RIGHT_SQUARE = ']';
 
    Stack s = new Stack(100);
    char ch;
    int i = 0;
    boolean failed = false;
 
    FileInputStream fstream = new FileInputStream("test.txt");
 
    DataInputStream in = new DataInputStream(fstream);
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
    String strLine;
 
    while ((ch = (char)br.read()) != (char)-1 )
       if (!s.full()) 
       {
         for (i=0; !failed && (i < expression.length( )); i++)
          {
       	     switch (expression.charAt(i))
       	     {
       		  case LEFT_PARENT:
       		  case LEFT_CURLY:
       		  case LEFT_SQUARE:
       		       s.push(expression.charAt(i));
       		       break;
       		  case RIGHT_PARENT:
       		 if (s.empty() || (s.pop() != LEFT_PARENT))
       			   failed = true;
       			   break;
       	  	  case RIGHT_CURLY:
       		 if (s.empty() || (s.pop() != LEFT_CURLY))
       			   failed = true;
       			   break;
       		  case RIGHT_SQUARE:
       		 if (s.empty() || (s.pop() != LEFT_SQUARE))
       			   failed = true;
       			   break;     			 	
         	} 	
          }
       	}
       	   return (s.empty() && !failed);
     }             
}

Stack Class

class Stack {
   private int maxStack;
   private int emptyStack;
   private int top;
   private char[] items;
 
 
 
 
   public Stack(int size) {
      maxStack= size;
      emptyStack = -1;
      top = emptyStack;
      items = new char[maxStack];
   }
 
 
 
   public void push(char c) {
      items[++top] = c;
   }
 
   public char pop() {
      return items[top--];
   }
 
   public boolean full()  {
      return top + 1 == maxStack;
   }
 
   public boolean empty()  {
      return top == emptyStack;
   }
}

I still receive a blank screen when I try to print.

my latest modification to print is this....

import java.io.* ;
 
public class Stackmain 
{
 
   // public Stackmain() 
   // {
 
 
   // }
    public static boolean main(String expression) throws IOException 
    {
 
    final char LEFT_PARENT = '(';
    final char RIGHT_PARENT = ')';
    final char LEFT_CURLY = '{';
    final char RIGHT_CURLY = '}';
    final char LEFT_SQUARE = '[';
    final char RIGHT_SQUARE = ']';
 
    Stack s = new Stack(100);
    char ch;
    int i = 0;
    boolean failed = false;
 
    FileInputStream fstream = new FileInputStream("test.txt");
 
    DataInputStream in = new DataInputStream(fstream);
    BufferedReader br = new BufferedReader(new InputStreamReader(in));
 
 
 
    while ((ch = (char)br.read()) != (char)-1 )
    {
       if (!s.full()) 
       {
 
         for (i=0; !failed && (i < expression.length( )); i++)
          {
       	     switch (expression.charAt(i))
       	     {
       		  case LEFT_PARENT:
       		  case LEFT_CURLY:
       		  case LEFT_SQUARE:
       		       s.push(expression.charAt(i));	  
       		       break;
       		  case RIGHT_PARENT:
       		 if (s.empty() || (s.pop() != LEFT_PARENT))
       			   failed = true;
       			   break;
       	  	  case RIGHT_CURLY:
       		 if (s.empty() || (s.pop() != LEFT_CURLY))
       			   failed = true;
       			   break;
       		  case RIGHT_SQUARE:
       		 if (s.empty() || (s.pop() != LEFT_SQUARE))
       			   failed = true;
       			   break;    
 
 
         	} 	
 
          }
     }
 
}
 
 
if (failed == true)
{
	System.out.println("Expression does not match");
}
if (failed == false)
{
	System.out.println("Expression does match");
}
 
return (s.empty() && !failed);
}
}