为什么显示无法解析的错误，已经引用函数了

Question

#include<string>
#include<vector>
#include<algorithm>
#include<stack>
#include<stdlib.h>
#include "qtwidgetsapplication1.h"
using namespace std;

string format(string str)
{
    for (int i = 0; i < str.length(); i++)
    {
        if (str[i] == '-')
        {
            if (i == 0)
            {
                str.insert(0, 1, '0');
            }
            else if (str[i - 1] == '(')
            {
                str.insert(i, 1, '0');
            }
        }
        return str;
    }
}

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



vector<string> hz(string str)
{
    vector<string> vs;
    stack<char> st;
    for (int i = 0; i < str.length(); i++)
    {
        string tmp = "";
        switch (str[i])
        {
        case'+':
        case'-':
        case'*':
        case'/':
            if (st.empty() || st.top() == '(')
            {
                st.push(str[i]);
            }
            else
            {
                while (!st.empty() && prior(st.top()) >= prior(str[i]))
                {
                    tmp += st.top();
                    vs.push_back(tmp);
                    st.pop();
                    tmp = "";
                }
                st.push(str[i]);
            }
            break;
        case'(':
            st.push(str[i]);
            break;
        case')':
            while (st.top() != '(')
            {
                tmp += st.top();
                vs.push_back(tmp);
                st.pop();
                tmp = "";
            }
            st.pop();
            break;
        default:
            if ((str[i] >= '0' && str[i] <= '9'))
            {
                tmp += str[i];
                while (i + 1 < str.size() && str[i + 1] >= '0' && str[i + 1] <= '9' || str[i + 1] == '.')
                    tmp = str[i + 1];
                ++i;
            }
            vs.push_back(tmp);
        }
    }
    while (!st.empty())
    {
        string tmp = "";
        tmp += st.top();
        vs.push_back(tmp);
        st.pop();
    }
    return vs;
}
double result(vector<string> bh)
{
    stack<double> st;
    double num, op1, op2;
    for (int i = 0; i < bh.size(); i++)
    {
        string tmp = bh[i];
        if (tmp[0] >= '0' && tmp[0] <= '9')
        {
            num = atof(tmp.c_str());
            st.push(num);
        }
        else if (bh[i] == "+")
        {
            op2 = st.top();
            st.pop();
            op1 = st.top();
            st.pop();
            st.push(op1 + op2);
        }
        else if (bh[i] == "-")
        {
            op2 = st.top();
            st.pop();
            op1 = st.top();
            st.pop();
            st.push(op1 - op2);
        }
        else if (bh[i] == "*")
        {
            op2 = st.top();
            st.pop();
            op1 = st.top();
            st.pop();
            st.push(op1 * op2);
        }
        else if (bh[i] == "/")
        {
            op2 = st.top();
            st.pop();
            op1 = st.top();
            st.pop();
            st.push(op1 / op2);
        }
        return st.top();
    }
}

double solve(string str)
{
    str = format(str);
    vector<string>bh = hz(str);
    double k = result(bh);
    return k;
}

void QtWidgetsApplication1::numbuttonPress()
{
    int flag;
    QString expression;
    expression = ui.lineEdit->text();
    QPushButton* btn = qobject_cast<QPushButton*>(sender());
    QString number = btn->text();
    flag = expression.indexOf("=");
    if (expression == "0.0")
        ui.lineEdit->setText(number);
    else if (flag != -1)
    {
        ui.lineEdit->setText(expression.right(expression.size() - 1 - flag));
        ui.lineEdit->insert(number);
    }
    else
        ui.lineEdit->insert(number);
}
void QtWidgetsApplication1::clearPress()
{
    ui.lineEdit->setText("0.0");
}
void QtWidgetsApplication1::backPress()
{
    QString expression;
    expression = ui.lineEdit->text();
    if (expression == "0.0")
        return;
    else if (expression == "")
    {
        ui.lineEdit->setText("0.0");
    }
    else
    {
        expression = expression.left(expression.size() - 1);
        ui.lineEdit->setText(expression);
    }
}

void QtWidgetsApplication1::eqlbtnPress()
{
    ui.lineEdit->insert("=");
    QString expression;
    expression = ui.lineEdit->text();
    double result;
    result = solve(expression.toStdString());
    if ((int)result == result)
    {
        ui.lineEdit->insert(QString::number((int)result, 10, 0));
    }
    else
    {
        ui.lineEdit->insert(QString::number((int)result, 10, 6));
    }
}

![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/365457953496164.png "#left")

Answer 1

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