LNK2019 error using multiple source files

Hello community,

I can't run my hello world program, I get LNK2019 error.

main.cpp

Code:

---

#include <QCoreApplication>
#include "hello.h"
 
int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);
 
    Hello *hi = new Hello();
 
    return app.exec();
}

---

hello.h

Code:

---

#ifndef HELLO_H
#define HELLO_H
 
class Hello{
public:
    Hello();
};
 
#endif // HELLO_H

---

hello.cpp

Code:

---

#include <iostream>
 
class Hello{
public:
    Hello(){
        std::cout << "hello world" << std::endl;
    }
};

---

myproject.pro

Code:

---

QT -= gui
 
CONFIG += c++11 console
CONFIG -= app_bundle
DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += \
        hello.cpp \
        main.cpp
 
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
 
HEADERS += \
    hello.h

---

It works fine without creating Hello object.

Did you run qmake again after changing your .pro file to add the hello.* entries?

You define your class Hello a second time in hello.cpp