Code to check if a piece of code is legal.

[vahshir]

Hey guys I'm having a bit of trouble with this and not sure if I'm doing it right. I know there is an easier way but I'm not sure how to do it. Also for the stack.peek() == '{' is that right because when I compile it, it comes up with incomparable types: java.lang.Object and char.

Any help would be appreciated.

import java.util.Stack;
/** 
 * 
 * @author () 
 * @version () 
 */ 
public class Brackets 
{ 
    private String code;

    /** 
     * Constructor for objects of class Brackets 
     */ 
    public Brackets(String text1) 
    {
        code = text1; 
    } 
    
    /**
     * checks if the code is legit or not.
     *@return if it is legal or not.
     */

    public boolean isLegal()
    {
          boolean legal = false;
          Stack stack = new Stack(); 
          for( int index = 0; index < code.length();index++) 
          { 
                char ch = code.charAt(index); 
                if(ch == '{')
                {
                    stack.push(ch);
                    legal = true;
                }
                else if(ch == '(')
                {
                    stack.push(ch);
                }
                else if(ch == '[' && legal == true)
                {
                    stack.push(ch);
                }
                else if((ch == ']') && (stack.peek() == '[') && legal == true)
                {
                    stack.pop();
                }
                else if((ch == ')') && (stack.peek() == '(') && legal == true)
                {
                    stack.pop();
                }
                else if((ch == '}') && (stack.peek() == '{') && legal == true)
                {
                    stack.pop();
                }
                else
                {
                    legal = false;
                }
          }
          return legal;
    }
}

[JosAH]

You are using a 'raw' Stack, i.e. it can only store and retrieve Objects; generics can solve this little issue: use a Stack<Character> instead and autoboxing does the implicit casting for you.

kind regards,

Jos

[vahshir]

Thanks very much got it working now. i knew it was something simple.
Cheers for that
Vahshir.

[Eranga]

Please use code tags next time.