balanced parentheses in java

Check for balanced parentheses in java containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, check if the input string is valid and return true if the string is balanced otherwise return false.

There are following step Perform :-

First, we create the object of character stack.

Traverse the input string and convert into character from str.charAt() method.

We check stack is empty and push the character to stack.

Now we push the current character to stack if it is a starting bracket(‘(‘ or ‘{‘ or ‘[‘).

We pop the current character from the stack if it is a closing bracket. If the popped character doesn’t match with the starting bracket, brackets are not balanced.

Once the traversing is finished and there are some starting brackets left in the stack, the brackets are not balanced.

				
					import java.util.Stack;

public class BalancedParanthsisMain {
	public static void main(String[] args) {
		
		String str = "{[()]}";
		Stack<Character> st = new Stack<Character>();
		for (int i = 0; i < str.length(); i++) {
			char ch = str.charAt(i);
			if (st.empty()) {
				st.push(str.charAt(i));
			} else if (ch == '{' || ch == '[' || ch == '(') {
				st.push(ch);
			} else if (ch == '}' && st.peek() == '{') {
				st.pop();
			} else if (ch == ']' && st.peek() == '[') {
				st.pop();
			} else if (ch == ')' && st.peek() == '(') {
				st.pop();
			}
		}
		if (st.empty()) {
			System.out.println("Given input String " + str + " is well formed");
		} else {
			System.out.println("Given input String " + str + " not well formed");
		}
	}
}

Output :- Given input String {[()]} is well formed