四则运算
import java.util.Random; import java.util.Scanner; public class si'ze'yun'suan { public static void res(){ System.out.println("1.显示结果\t2.直接开始下一题"); } public static void main (String[] arge){ int i=1; if(i<=30)//保证只是随机30道四则运算题目 { System.out.println("*****请选择要随机生成的算法*****"); System.out.println("1,加法\t2,减法\t3,乘法\t4,除法"); System.out.println("*******************************"); Scanner sc=new Scanner(System.in); int s = sc.nextInt(); double result=0; Random r = new Random(); int a = r.nextInt(100); int b =r.nextInt(100); switch(s){ case 1:System.out.println(+a+"+"+b+"=?");result =a+b;res();break; case 2:System.out.println(+a+"-"+b+"=?");result =a-b;res();break; case 3:System.out.println(+a+"*"+b+"=?");result =a*b;res();break; case 4:System.out.println(+a+"/"+b+"=?");{float c=a;float d=b;result=c/d;}res();break; default:System.out.println("输入有误,重新开始");main(null);break; } Scanner select =new Scanner(System.in); int se =select.nextInt(); switch (se){ case 1:System.out.println("本题的结果:"+result);main(null);break; case 2:main(null);break; default:System.out.println("输入有误,重新开始");main(null); } i++; } } }