写一个栈将中缀表达式转换为后缀表达式并求值的代码

好的，以下是代码实现：

# 定义运算符优先级
priority_dict = {'(': 0, '+': 1, '-': 1, '*': 2, '/': 2, '%': 2, '^': 3}

# 中缀表达式转换为后缀表达式并求值
def infix_to_postfix(expression):
    postfix_list = []
    operator_stack = []
    for i in expression:
        if i.isdigit():
            postfix_list.append(i)
        elif i == '(':
            operator_stack.append(i)
        elif i == ')':
            while operator_stack[-1] != '(':
                postfix_list.append(operator_stack.pop())
            operator_stack.pop()
        else:
            while operator_stack and priority_dict[i] <= priority_dict[operator_stack[-1]]:
                postfix_list.append(operator_stack.pop())
            operator_stack.append(i)
    while operator_stack:
        postfix_list.append(operator_stack.pop())
    postfix_expression = ''.join(postfix_list)
    return postfix_expression

# 计算后缀表达式
def postfix_eval(expression):
    operand_stack = []
    for i in expression:
        if i.isdigit():
            operand_stack.append(int(i))
        else:
            operand2 = operand_stack.pop()
            operand1 = operand_stack.pop()
            result = 0
            if i == '+':
                result = operand1 + operand2
            elif i == '-':
                result = operand1 - operand2
            elif i == '*':
                result = operand1 * operand2
            elif i == '/':
                result = operand1 / operand2
            elif i == '%':
                result = operand1 % operand2
            elif i == '^':
                result = operand1 ** operand2
            operand_stack.append(result)
    return operand_stack.pop()

# 测试代码
expression = input('请输入中缀表达式：')
postfix_expression = infix_to_postfix(expression)
print('中缀表达式转换为后缀表达式：', postfix_expression)
result = postfix_eval(postfix_expression)
print('计算结果为：', result)

请注意，该代码只能处理数字和加减乘除取模幂等基本运算符，不能处理括号外的运算符优先级问题。如果表达式中包含非法字符或表达式格式不正确，代码将会报错。