java中使用数组实现堆栈时切换大小写

public class StackExample {
    private char[] stackArray;
    private int top;

    public StackExample(int size) {
        stackArray = new char[size];
        top = -1;
    }

    public void push(char element) {
        if (top < stackArray.length - 1) {
            if (Character.isUpperCase(element)) {
                element = Character.toLowerCase(element);
            } else if (Character.isLowerCase(element)) {
                element = Character.toUpperCase(element);
            }
            stackArray[++top] = element;
        } else {
            System.out.println("Stack is full. Cannot push element: " + element);
        }
    }

    public char pop() {
        if (top >= 0) {
            return stackArray[top--];
        } else {
            System.out.println("Stack is empty. Cannot pop element.");
            return '\0';
        }
    }

    public static void main(String[] args) {
        StackExample stack = new StackExample(5);
        stack.push('A');
        stack.push('b');
        stack.push('C');
        stack.push('d');
        stack.push('E');

        System.out.println("Popped elements from the stack:");
        System.out.println(stack.pop());
        System.out.println(stack.pop());
        System.out.println(stack.pop());
        System.out.println(stack.pop());
        System.out.println(stack.pop());
        System.out.println(stack.pop());
    }
}