练习口算

import java.util.*;import java.text.DecimalFormat;public class clac {public static void main(String[] args){int count =0;Scanner in = new Scanner(System.in);System.out.println("输入计算次数:");int total = in.nextInt();long startMili = System.currentTimeMillis();for(int i=0;i<total;i++){DecimalFormat df = new DecimalFormat("#.00");double j = (Math.random()*10000)/100;System.out.println("计算:"+df.format(j));String k = df.format(100-j);String input = in.next();if(input.equals(k)){count++;}else{System.out.printf("结果:%s\n\n",k);}}long endMili = System.currentTimeMillis();double timeUse = (endMili-startMili)*1.0/1000;System.out.printf("题目总数:%d 总耗时:%.2f秒\n平均耗时:%.2f 正确率:%.2f%%",total,timeUse,timeUse/total,count*1.0*100/total);in.close();}}