qt 仿windows计算器的简单版本。-to qt the imitation windows calculator simple version.

实现整数（包括负数）的四则运算，使用Qt制作的图形界面。算式正确输出结果并打印二叉树。算式错误输出提示-Integer (including negative) of the four operations, making use of Qt graphical interface. The correct formula output and print two fork tree. Formula error output prompt

简单计算器，实现+、—、*、/运算，具有保存记忆功能，用qt做得-Simple calculator, to achieve+,-,*,/operations, save memory function, done with qt

用Qt设计的简单计算器。主要让大家熟悉设计流程哈。-With simple calculator Qt Designer. Mainly familiar with the design process ha.