heyy..

i am getting error on line 51 "Stack<Character> stack = new Stack<Character>();"..how can i fix it? please help.

import java.io.IOException;
import java.util.Scanner;

public class SymbolChecker {
    private String enter;
    
  public SymbolChecker(String in) {
    enter = in;
  }
Scanner input = new Scanner(System.in);
  public void check() {
    int stackSize = enter.length();
    Stack theStack = new Stack(stackSize);

    for (int j = 0; j < enter.length(); j++)
    {
      char ch = enter.charAt(j);
      switch (ch) {
      case '{': // opening symbols
      case '[':
      case '(':
        theStack.push(ch); // push them
        break;

      case '}': // closing symbols
      case ']':
      case ')':
        if (!theStack.isEmpty()) // if stack not empty,
        {
          char chx = theStack.pop(); // pop and check
          if ((ch == '}' && chx != '{') || (ch == ']' && chx != '[')
              || (ch == ')' && chx != '('))
            System.out.println("Error: " + ch + " at " + j);
        } else
          // prematurely empty
          System.out.println("Error: " + ch + " at " + j);
        break;
      default: // no action on other characters
        break;
      }
    }
    if (!theStack.isEmpty())
      System.out.println("Error: missing right delimiter");
  }

  public static void main(String[] args) throws IOException {
    String input = "{Java [Source] (and) {[(Support)]}}";
    SymbolChecker theChecker = new SymbolChecker(input);
    theChecker.check();

    Stack<Character> stack = new Stack<Character>();
String s = "{[]}{{}]";
//s = "{}{}{[]}";
int index = 0;
while(index < s.length()) {
char ch = s.charAt(index);
if(ch == '{' || ch == '[' || ch == '(') {
stack.push(ch);
} else {
if(stack.empty()) {
System.out.println("error");
continue;
}
// pop an item from stack
char ch1 = stack.pop();
// check if it's a matching pair
if(ch1 == '{' && ch != '}' ||
ch1 == '[' && ch != ']' || ch1 == '(' && ch != ')') {
System.out.println("error unmatched " + ch);
}
}
index++;
}
if(!stack.empty()) {
System.out.println("unbalanced symbols");
}
}
  }


class Stack {
  private int maxSize;

  private char[] stackArray;

  private int top;

  public Stack(int max) {
    maxSize = max;
    stackArray = new char[maxSize];
    top = -1;
  }

  public void push(char j) {
    stackArray[++top] = j;
  }

  public char pop() {
    return stackArray[top--];
  }

  public char peek() {
    return stackArray[top];
  }

  public boolean isEmpty() {
    return (top == -1);
  }
}

Your Stack implementation is not generic i.e. doesn't accept type parameters. Or is it that you are planning on using the Stack implementation provided by the standard library?