12.21作业

            //1.输入圆柱体的底面半径和高，求体积？
            Console.Write("请输入圆柱体的半径:");
            string r = Console.ReadLine();

            Console.Write("请输入圆柱体的高度:");
            string h = Console.ReadLine();

            int a = Convert.ToInt32(r);
            double b = Convert.ToDouble(h);

            const double p = 3.14;

            Console.WriteLine("圆柱体的体积:V=" + a * a * b * p + "m*3");

            //2.建造游泳池，泳池半径a，求泳池护栏长度？
            Console.Write("请输入游泳池的半径:");
            string a = Console.ReadLine();
            double r = Convert.ToDouble(a);

            const double π = 3.14;
            Console.WriteLine("游泳池护栏的周长:C=" + 2 * π * r + "m");

            //3.广场砖面积？
            const double π = 3.14;

            Console.Write("请输入游泳池的半径:");
            string a = Console.ReadLine();
            double r = Convert.ToDouble(a);

            Console.Write("请输入大广场的半径：");
            string b = Console.ReadLine();
            double R = Convert.ToDouble(b);

            Console.WriteLine("广场砖的面积:S=" + (π * R * R - π * r * r) + "m*2");



            //4.护栏造价25元/米，广场砖85元/平，求护栏和广场砖共花钱数？
            Console.Write("请输入游泳池的半径:");
            string a = Console.ReadLine();
            double r = Convert.ToDouble(a);

            const double π = 3.14;
            Console.WriteLine("游泳池护栏的周长:C=" + 2 * π * r + "m");
            Console.WriteLine("护栏的花费是:"+25*2*π*r+"元");

            Console.Write("请输入大广场的半径：");
            string b = Console.ReadLine();
            double R = Convert.ToDouble(b);

            Console.WriteLine("广场砖的面积:S=" + (π * R * R - π * r * r) + "m*2");
            Console.WriteLine("广场砖的花费是:" + 85 * (π * R * R - π * r * r) + "元");