已知圆半径r=2.5 圆柱高h=4,求圆的周长，面积，圆球体积，圆柱体积，用cin输入要计算的项目，然后输出计算结果，输入输出时要有文字提示-Known round cylinder radius r = 2.5 high h = 4, for the circumference of the circle, area, ball size, cylindrical volume, use cin input to calculate project, and then output the c