scrollAreaWidgetContents not available when scroll area declared in code

[aurora]

I used scrollArea widget before, that time i created it in designer and to add the widgets into it i did as below

ui->scrollAreaWidgetContents->layout()->addWidget(checkbox);
    ui->scrollAreaWidgetContents->layout()->addWidget(ComboOperator);

ui->scrollAreaWidgetContents->layout()->addWidget(checkbox);
    ui->scrollAreaWidgetContents->layout()->addWidget(ComboOperator);

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But now i wanted to create one more scroll area programattically(without designer)
I declared as below...

QScrollArea *sarea=new QScrollArea;
   sarea->layout()->addWidget(checkbox);
sarea->layout()->addWidget(ComboOperator);

QScrollArea *sarea=new QScrollArea;
   sarea->layout()->addWidget(checkbox);
sarea->layout()->addWidget(ComboOperator);

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And when i tried to put inside it, program was crashing.
Here i didnt get option to use scrollAreaWidgetContents, as it was available in designer....
Please tell me what wrong here...