这个是一个计算圆面积的Qt程序只要你在Qlineedit中输入需要计算的半径长度，就可算出结果-This is a Qt program to calculate the area of ​ ​ a circle as long as you enter the need to calculate the length of the radius of Qlineedit in, you can calculate the results

QT做的简易计算器，实现简单的计算，建议在LINUX下运行-QT do simple calculator, the realization of simple calculation, it is suggested that under the LINUX operation