QT5对QinputDialog和Qmessagebox的未识别引用.错误

我忙于大学作业，我是QT，C 的新手，我需要：在单独的标题和源文件中定义和实现地址类

我与QT4和QT5混淆了，因为规定的教科书提供了QT4中的所有示例，但是我们需要使用QT5进行编码。我一直遇到错误，最新错误是：

 error: undefined reference to 
 Dialog7getTextEP7QWidgetRK7QStringS4_N9QLineEdit8EchoModeES4_
 Pb6QFlagsIN2Qt10WindowTypeEES8_INS9_15InputMethodHintEE'
 error: undefined reference to 
 MessageBox11informationEP7QWidgetRK7QStringS4_6QFlagsINS_
 14StandardButtonEES6
 collect2.exe:-1: error: error: ld returned 1 exit status

我很困惑和陷入困境，如果有人可以朝着正确的方向引导我，我将非常感谢它，这是我到目前为止的代码：

标题文件：

#ifndef ADDRESS_H_
#define ADDRESS_H_
#include <QString>
#include <QFile>
#include <QStringList>
#include <QtCore>
QTextStream cout(stdout);
QTextStream cerr(stderr);
class Address{
public:
Address();
void setLines(QString ad, QString sep);
QString getPostalCode() const;
QString toString(QString sep) const;
static bool isPostalCode(QString pc);
private:
static QStringList lines;
};
#endif // ADDRESS_H_

主文件：

#include "address.h"
#include <iostream>
#include <QFile>
#include <sstream>
#include <fstream>
#include <QStringList>
#include <QString>
#include <QTextStream>
#include <QCoreApplication>
#include <QtWidgets/QInputDialog>
#include <QtWidgets/QMessageBox>
#include <QtWidgets/QLineEdit>
Address::Address(){}
void Address::setLines(QString ad, QString sep){
QStringList lines;
lines = ad.split(sep, QString::SkipEmptyParts);
}
QString Address::getPostalCode() const{
QStringList lines;
return lines.last();
}
QString Address::toString(QString sep) const{
QStringList lines;
return lines.join(sep);
}
bool Address::isPostalCode(QString pc){
if (pc >= "0" && pc <= "9999")
    return true;
else
    return false;
}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    while(true)
{
    QString userInput = QInputDialog::getText(0,"Address Input","Please 
    enter your address:");
    QLineEdit::EchoMode ok = QLineEdit::Normal;
    QString();
    if(ok && !userInput.isEmpty())
{
    Address ad;
    QMessageBox::information(0, "User Address",ad.toString(userInput));
}
}
return 0;
}