多个减法测试题， 详细解析，output新知识

package com.baidu;
import java.util.Scanner;
public class SubtractionzLoop {
    public static void main(String[] args) {
        final int NUMBER_OF_QUESTIONS = 6;   //定义一个常量，计算机道题目；
        int correctCount = 0;   //计算正确的答案是几个；
        int count = 0;   //计算一共有几个；
        long startTime = System.currentTimeMillis();  //记录开始产生的时间
        String output = " ";  //输出字符串是空的
        Scanner input = new Scanner(System.in);   //输入 系统扫描键盘录入数字；
        
        while(count<NUMBER_OF_QUESTIONS) {
            //生成两个随机的单位数整数;
            int number1 = (int)(Math.random()*10);
            int number2 = (int)(Math.random()*10);
            
            if(number1<number2) {
                //比较大小进行交换；
                int temp = number1;
                number1 = number2;
                number2 = temp;
            }
            //提示学生回答,计算问题
            System.out.println("what is " + number1 + " - " + number2 + " ? ");
            int answer = input.nextInt();//输入相应的结果；
            
            if(number1-number2 == answer) {
                //评分答案并显示结果;
                System.out.println(" your are current ");
                correctCount++;   //增加正确的答案计数
                
            }
            else
                System.out.println("your answer is wrong.\n"+ number1 + " - "+ number2 + " should be "+ (number1-number2));
            
            count++;   //增加问题数
            // 
            // 9 - 2 = 7(correct)  or  5(wrong)
            output+="\n"+number1+"-"+number2+"="+answer+ ((number1-number2==answer)?"correct":"wrong");
        }
        
        long endTime = System.currentTimeMillis();   //记录产生的时间
        long testTime = endTime - startTime;   //记录测试时间
        //Correct count is     correctCount
        //\nTest time is    testTime/1000  second\n   output
        
        System.out.println("Correct count is "+ correctCount + "\nTest time is " + testTime/1000 + "second\n" + output);
    }

}

package com.baidu;
import java.util.Scanner;
public class SubtractionzLoop {
    public static void main(String[] args) {
        final int NUMBER_OF_QUESTIONS = 6;   //定义一个常量，计算机道题目；
        int correctCount = 0;   //计算正确的答案是几个；
        int count = 0;   //计算一共有几个；
        long startTime = System.currentTimeMillis();  //记录开始产生的时间
        String output = " ";  //输出字符串是空的
        Scanner input = new Scanner(System.in);   //输入 系统扫描键盘录入数字；
        
        while(count<NUMBER_OF_QUESTIONS) {
            //生成两个随机的单位数整数;
            int number1 = (int)(Math.random()*10);
            int number2 = (int)(Math.random()*10);
            
            if(number1<number2) {
                //比较大小进行交换；
                int temp = number1;
                number1 = number2;
                number2 = temp;
            }
            //提示学生回答,计算问题
            System.out.println("what is " + number1 + " - " + number2 + " ? ");
            int answer = input.nextInt();//输入相应的结果；
            
            if(number1-number2 == answer) {
                //评分答案并显示结果;
                System.out.println(" your are current ");
                correctCount++;   //增加正确的答案计数
                
            }
            else
                System.out.println("your answer is wrong.\n"+ number1 + " - "+ number2 + " should be "+ (number1-number2));
            
            count++;   //增加问题数
            // 
            // 9 - 2 = 7(correct)  or  5(wrong)
            output+="\n"+number1+"-"+number2+"="+answer+ ((number1-number2==answer)?"correct":"wrong");
        }
        
        long endTime = System.currentTimeMillis();   //记录产生的时间
        long testTime = endTime - startTime;   //记录测试时间
        //Correct count is     correctCount
        //\nTest time is    testTime/1000  second\n   output
        
        System.out.println("Correct count is "+ correctCount + "\nTest time is " + testTime/1000 + "second\n" + output);
    }

}

 

 

 

 

 

 

 

 

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1.IO流是用来处理设备之间的数据传输；输入流（Input）：只能从中读取数据，而不能向其写入数据

                                                                输出流（Output）：只能向其写入数据，而不能从中读取数据

2.java对数据的操作是通过流的方式、

3.java用于操作流的对象都在IO包中。

4.流按照操作数据分为两种：字节流和字符流；按照流向分为输入流和输出流