javase程序设计上机作业1

package javaxgp.teacher.test;

import java.math.BigInteger;
import java.util.Scanner;
import java.util.TreeSet;

/**
 * java课第一次作业
 */
public class Demo1 {
    public static void main(String[] args) {
        /**
         *进制转换
         */
//        method1();

        /**
         * 寻找素数
         */
//        method2();

        /**
         * 计算PI
         */
//        method3();

        /**
         * 排序问题
         */
        method4();

        /**
         * 5，傻瓜操做，略
         */
    }

    private static void method4() {
        TreeSet<Integer> treeSet = new TreeSet();
        Scanner scanner = new Scanner(System.in);
        for(int i = 0;i < 10;i++) {
            System.out.println("请输入第" + (i + 1) + "个整数");
            treeSet.add(scanner.nextInt());
        }
        for (Integer out : treeSet) {
            System.out.println("排序结果:");
            System.out.print(out + "	");
        }
    }

    private static void method3() {
        double pi=0.0d;
        for(int i=1;i<=1000000;i++) {
            pi+=Math.pow(-1,(i+1))*4/(2*i-1);
        }
        System.out.println("近似pi = " + pi);
        System.out.println("math库的pi = " + Math.PI);
        System.out.println("误差值（pi - Math.PI） " + (pi -Math.PI));
    }

    private static void method2() {
        BigInteger init = BigInteger.ONE;
        while ((init = init.nextProbablePrime()).compareTo(new BigInteger("1000")) == -1) {
            System.out.println(init);
        }
    }

    private static void method1() {
        try {
            long input = 0;
            String num2 = null;
            String num8 = null;
            String num10 = null;
            String num16 = null;

            Scanner scanner = new Scanner(System.in);
            while(true) {
                System.out.println("请输入要转换的数字(输录字母q退出使用)：");
                String str = scanner.nextLine();
                if("q".equals(str)) {
                    break;
                }
                System.out.println("该数字的进制为（2，10，8，16）：");
                int num = scanner.nextInt();
                if(!str.isEmpty()) {
                    switch (num) {
                        case 2:input = Long.parseLong(str, num);break;
                        case 8:input = Long.parseLong(str, num);break;
                        case 10:input = Long.parseLong(str, num);break;
                        case 16:input = Long.parseLong(str, num);break;
                    }
                    num2 = Long.toBinaryString(input);
                    num8 = Long.toOctalString(input);
                    num10 = Long.toString(input);
                    num16 = Long.toHexString(input);

                    System.out.println("该数字的2进制为：" + num2);
                    System.out.println("该数字的8进制为：" + num8);
                    System.out.println("该数字的10进制为：" + num10);
                    System.out.println("该数字的16进制为：" + num16);
                }
            }

        }catch (Exception e) {
            System.out.println("你的输录有误，程序退出！");
        }finally {
            System.out.println("欢迎你的再次使用！");
        }
    }
}