达内前期训练营课堂练习代码

package com.tarena.lx02; import java.util.InputMismatchException; import java.util.Scanner; import org.junit.Test; public class computer { @Test public void tst_comp() { Scanner sc = new Scanner(System.in); // 打印系统信息 printInfo(); String str = null; int num = 0; while (true) { try { str = sc.next(); num = Integer.parseInt(str); } catch (Exception E) { System.out.println("对不起,输入有误"); printInfo(); continue; } switch (num) { case 0: System.out.print("程序已经退出"); System.exit(-1); case 1: System.out.println(" 系统提示："); try { System.out.println(" 请输入被加数"); String str1 = sc.next(); System.out.println(" 请输入加数："); String str2 = sc.next(); int x = Integer.parseInt(str1); int y = Integer.parseInt(str2); int sum = x + y; System.out.println("你输入的" + x + "和" + y + "=" + sum); } catch (Exception e) { System.out.println(e.toString()); System.out.println("对不起，输入有误！"); } printInfo(); break; case 2: System.out.println(" 系统提示："); System.out.println(" 请输入被减数"); try { String str1 = sc.next(); System.out.println(" 请输入减数："); String str2=sc.next(); int x = Integer.parseInt(str1); int y = Integer.parseInt(str2); int cha = x - y; System.out.println("你输入的" + x + "-" + y + "=" + cha); } catch (Exception E) { System.out.println("对不起，输入有误！"); } printInfo(); break; case 3: System.out.println(" 系统提示："); try { System.out.println(" 请输入被乘数"); String str1 = sc.next(); System.out.println(" 请输入乘数："); String str2 = sc.next(); int x = Integer.parseInt(str1); int y = Integer.parseInt(str2); int ji = x * y; System.out.println("你输入的" + x + "*" + y + "=" + ji); } catch (Exception E) { System.out.println("对不起，输入有误！"); } printInfo(); break; case 4: System.out.println(" 系统提示："); System.out.println(" 请输入被除数"); try { String str1 = sc.next(); System.out.println(" 请输入除数："); String str2 = sc.next(); double x = Double.parseDouble(str1); double y = Double.parseDouble(str2); double shang = x / y; System.out.println("你输入的" + x + "/" + y + "=" + shang); } catch (Exception e) { System.out.println("对不起，输入有误"); } printInfo(); break; case 5: System.out.println(" 系统提示："); System.out.println(" 请输入被除数"); try { String str1 = sc.next(); System.out.println(" 请输入除数："); String str2 = sc.next(); int x = Integer.parseInt(str1); int y = Integer.parseInt(str2); int yuShu = x % y; System.out.println("你输入的" + x + "%" + y + "=" + yuShu); } catch (InputMismatchException e) { System.out.println("对不起，输入有误"); } printInfo(); break; default: printInfo(); } System.out.println(" 请输入被乘数"); } } public static void printInfo() { System.out .println(" 菜单\n 1代表加法运算\n 2代表减法运算\n 3代表乘法运算\n 4代表除法运算\n 5代表取余运算\n 0代表推出程序\n"); System.out.println("请选择："); } }