帮我用C++写一段代码，实现算术表达式的求解 给定一个算术表达式，通过程序求出最后的结果。 基本要求： (1)从键盘输入要求解的算术表达式如1+1 运算符号包括 + - * / 和mod，如1+1 (2)采用栈结构进行算术表达式的求解过程； (3)能够判断算术表达式正确与否； (4)对于错误表达式给出提示； (5)对于正确的表达式给出最后的结果；

好的，以下是C++代码实现算术表达式的求解：

#include <iostream>
#include <string>
#include <stack>
#include <cmath>

using namespace std;

bool isOperator(char c) {
    return (c == '+' || c == '-' || c == '*' || c == '/' || c == '%');
}

int getPriority(char op) {
    if (op == '*' || op == '/' || op == '%') {
        return 2;
    } else if (op == '+' || op == '-') {
        return 1;
    } else {
        return 0;
    }
}

bool isNumber(char c) {
    return (c >= '0' && c <= '9');
}

double calculate(double num1, double num2, char op) {
    double result;
    switch (op) {
        case '+':
            result = num1 + num2;
            break;
        case '-':
            result = num1 - num2;
            break;
        case '*':
            result = num1 * num2;
            break;
        case '/':
            result = num1 / num2;
            break;
        case '%':
            result = fmod(num1, num2);
            break;
        default:
            break;
    }
    return result;
}

double evaluate(string expression) {
    stack<double> numStack;
    stack<char> opStack;
    int i = 0;
    while (i < expression.length()) {
        if (isNumber(expression[i])) {
            double num = 0;
            while (i < expression.length() && isNumber(expression[i])) {
                num = num * 10 + (expression[i] - '0');
                i++;
            }
            numStack.push(num);
        } else if (isOperator(expression[i])) {
            while (!opStack.empty() && getPriority(opStack.top()) >= getPriority(expression[i])) {
                double num2 = numStack.top();
                numStack.pop();
                double num1 = numStack.top();
                numStack.pop();
                char op = opStack.top();
                opStack.pop();
                double result = calculate(num1, num2, op);
                numStack.push(result);
            }
            opStack.push(expression[i]);
            i++;
        } else if (expression[i] == '(') {
            opStack.push(expression[i]);
            i++;
        } else if (expression[i] == ')') {
            while (!opStack.empty() && opStack.top() != '(') {
                double num2 = numStack.top();
                numStack.pop();
                double num1 = numStack.top();
                numStack.pop();
                char op = opStack.top();
                opStack.pop();
                double result = calculate(num1, num2, op);
                numStack.push(result);
            }
            if (!opStack.empty()) {
                opStack.pop();
            } else {
                // 表达式不合法，缺少左括号
                cout << "Invalid expression" << endl;
                return 0;
            }
            i++;
        } else if (expression[i] == ' ') {
            i++;
        } else {
            // 表达式不合法，存在非法字符
            cout << "Invalid expression" << endl;
            return 0;
        }
    }
    while (!opStack.empty()) {
        if (opStack.top() == '(' || opStack.top() == ')') {
            // 表达式不合法，括号不匹配
            cout << "Invalid expression" << endl;
            return 0;
        }
        double num2 = numStack.top();
        numStack.pop();
        double num1 = numStack.top();
        numStack.pop();
        char op = opStack.top();
        opStack.pop();
        double result = calculate(num1, num2, op);
        numStack.push(result);
    }
    if (numStack.size() == 1) {
        return numStack.top();
    } else {
        // 表达式不合法，存在多余的操作符
        cout << "Invalid expression" << endl;
        return 0;
    }
}

int main() {
    string expression;
    cout << "Please input an arithmetic expression: ";
    getline(cin, expression);
    double result = evaluate(expression);
    if (result != 0) {
        cout << "The result is " << result << endl;
    }
    return 0;
}

使用方法：运行程序后，在命令行输入要求解的算术表达式（如1+1），按回车键即可求解。程序会先判断表达式是否合法，如果合法则输出最后的结果；如果不合法则给出提示。