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 radius r = 2.5 cylinder h, = 4, of circular perimeter, area, the sphere volume, cylinder volume, cin input to calculate the project, and then output the calculated results