Use QT to make simple addition, multiplication operations.

1. First Frame QT Application project

2. Then open the UI file in fomr file for editing using Qt Desinger

3. Since this program just click on the plus sign, minus the two buttons, so set up two signal slots

4. Then connect the signal slots

5. Finally, the realization of the method

Implementation of the code, it should be noted that the value obtained from Qlineedit is the QString type, need to convert to the desired type, I converted to a double type, and finally to Qlineedit assignment must also be QString type, so also to turn back, concrete implementation, from the code experience.

Use QT to make simple addition, multiplication operations.