import java.util.Random;
import java.util.Scanner;
public class RandomExample
{
public static void main(String[] args)
{
int count=0;
for(int i=0;i<30;i++){//生成随机两个随机数:Random random = new Random();Scanner scanner = new Scanner(System.in);int number1 = random.nextInt(99) + 1;int number2 = random.nextInt(99) + 1;int operator = random.nextInt(4);String opSymbol = "";int result = 0;boolean valid = true;
//进行四则运算:
switch (operator) {
case 0:
opSymbol = "+";
result = number1 + number2;
break;
case 1:
opSymbol = "-";
result = number1 - number2;
break;
case 2:
opSymbol = "*";
result = number1 * number2;
break;
case 3:
opSymbol = "/";
result = number1 / number2;
break;
}
//输入结果并检验
if (valid)
{
System.out.printf("请计算:%d %s %d = ?%n", number1, opSymbol, number2);
System.out.print("请输入你的答案:");
int userAnswer = scanner.nextInt();
if (userAnswer == result) {System.out.println("回答正确!");} else {System.out.printf("回答错误,正确答案是:%d%n", result);count++;}}}System.out.printf("错误的题数为:%d\n",count);System.out.printf("正确率是:%0.2f%%\n",(30-count)/30.0*100) ;
}
}