java实现中缀表达式转后缀表达式

好的，以下是 Java 实现中缀表达式转后缀表达式的代码：

import java.util.Stack;

public class InfixToPostfix {
    public static int precedence(char ch) {
        switch (ch) {
            case '+':
            case '-':
                return 1;
            case '*':
            case '/':
                return 2;
            case '^':
                return 3;
        }
        return -1;
    }

    public static String infixToPostfix(String expression) {
        StringBuilder result = new StringBuilder();
        Stack<Character> stack = new Stack<>();
        for (int i = 0; i < expression.length(); i++) {
            char ch = expression.charAt(i);
            if (Character.isLetterOrDigit(ch)) {
                result.append(ch);
            } else if (ch == '(') {
                stack.push(ch);
            } else if (ch == ')') {
                while (!stack.isEmpty() && stack.peek() != '(') {
                    result.append(stack.pop());
                }
                if (!stack.isEmpty() && stack.peek() != '(') {
                    return "Invalid Expression";
                } else {
                    stack.pop();
                }
            } else {
                while (!stack.isEmpty() && precedence(ch) <= precedence(stack.peek())) {
                    result.append(stack.pop());
                }
                stack.push(ch);
            }
        }
        while (!stack.isEmpty()) {
            result.append(stack.pop());
        }
        return result.toString();
    }

    public static void main(String[] args) {
        String expression = "a+b*(c^d-e)^(f+g*h)-i";
        System.out.println(infixToPostfix(expression));
    }
}