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public static double evaluate(String expression) {
    Deque<Double> operands = new ArrayDeque<>();
    Deque<Character> operators = new ArrayDeque<>();
    Deque<Character> precOperators = new ArrayDeque<>();
    precOperators.push('('); // Push an opening parenthesis to ensure all operators are popped

    for (int i = 0; i < expression.length(); i++) {
        char c = expression.charAt(i);
        if (Character.isDigit(c) || c == '.') {
            // Parse the number and push it to the operand stack
            int j = i;
            while (j < expression.length() && (Character.isDigit(expression.charAt(j)) || expression.charAt(j) == '.')) {
                j++;
            }
            double num = Double.parseDouble(expression.substring(i, j));
            operands.push(num);
            i = j - 1;
        } else if (c == '+' || c == '-' || c == '*' || c == '/' || c == '^' || c == '(') {
            // Check if the '-' operator denotes a negative number or a subtraction
            // operation
            if (c == '-' && (i == 0 || (!Character.isDigit(expression.charAt(i - 1)) && expression.charAt(i - 1) != ')'))) {
                // The '-' operator denotes a negative number, so parse the number and push it
                // to the operand stack
                int j = i + 1;
                while (j < expression.length() && (Character.isDigit(expression.charAt(j)) || expression.charAt(j) == '.')) {
                    j++;
                }
                double num = Double.parseDouble(expression.substring(i, j));
                operands.push(num);
                i = j - 1;
            } else {
                // Push the operator to the operator stack in order of precedence
                while (hasPrecedence(c, precOperators.peek())) {
                    char op = precOperators.pop();
                    double b = operands.pop();
                    double a = operands.pop();
                    double result = applyOp(op, a, b);
                    operands.push(result);
                }
                precOperators.push(c);
            }
        } else if (c == ')') {
            // Pop operators and operands until we reach the matching '('
            while (precOperators.peek() != '(') {
                char op = precOperators.pop();
                double b = operands.pop();
                double a = operands.pop();
                double result = applyOp(op, a, b);
                operands.push(result);
            }
            precOperators.pop(); // Discard the '('
        } else if (c == ' ') {
            // Ignore whitespace
        } else {
            throw new IllegalArgumentException("Invalid operator: " + c);
        }
    }

    // Perform any remaining operations
    while (precOperators.size() > 1) {
        char op = precOperators.pop();
        double b = operands.pop();
        double a = operands.pop();
        double result = applyOp(op, a, b);
        operands.push(result);
    }

    return operands.pop();
}