c – Qt / Qt Creator – 程序意外结束.坠毁

我在我的项目的main.cpp文件中编写了这段小代码：

#include <QApplication>
#include <QPushButton>

int main(int argc,char *argv[])
{
    QApplication app(argc,argv);

    QPushButton bouton("Hello !");
    bouton.show();

    return app.exec();

}

和.pro文件(默认情况下)：

SOURCES += 
    main.cpp

我试着让它运行,然后我得到了问题“QApplication：没有这样的文件或目录”.

然后,我在.pro文件中添加了“QT = widgets”(完整文件)：

SOURCES += 
    main.cpp
QT += widgets

现在我得到：

Starting <path to .exe>... 
The program has unexpectedly finished.
<path to .exe> crashed

请告诉我如何使它工作.
感谢您的阅读和帮助.

(操作系统：Windows 7,调试：桌面Qt 5.2.1 MinGW 32位)

编译输出：

16:06:54: Running steps for project test...
16:06:54: Configuration unchanged,skipping qmake step.
16:06:54: Starting: "C:QtToolsmingw48_32binmingw32-make.exe" 
C:/Qt/Tools/mingw48_32/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'C:/Users/PLD/Documents/PLD/Projets Codages/Qt/Qt/build-test-Desktop_Qt_5_2_1_MinGW_32bit-Debug'
mingw32-make[1]: Nothing to be done for 'first'.
mingw32-make[1]: Leaving directory 'C:/Users/PLD/Documents/PLD/Projets Codages/Qt/Qt/build-test-Desktop_Qt_5_2_1_MinGW_32bit-Debug'
16:06:55: The process "C:QtToolsmingw48_32binmingw32-make.exe" exited normally.
16:06:55: Elapsed time: 00:01.

应用输出：

Starting C:UsersPLDDocumentsPLDProjets CodagesQtQtbuild-test-Desktop_Qt_5_2_1_MinGW_32bit-Debugdebugtest.exe...
The program has unexpectedly finished.
C:UsersPLDDocumentsPLDProjets CodagesQtQtbuild-test-Desktop_Qt_5_2_1_MinGW_32bit-Debugdebugtest.exe crashed