本周四则运算各项功能已全部完成。
源码如下：
package homework;
import java.util.*;
import java.util.Scanner;
import javax.script.*;
import java.io.File;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.*;
public class math
{
private static int n,min,max,c,cc,kh=0,xz,zts=0,zcts=0;//题目数，数值范围（最小及最大），操作数个数，乘除，括号，选择菜单，总题数，总错题数
private static char[] d={'+','-','*','/'};//运算符
private static Scanner sc=new Scanner(System.in);
public static void main(String args[]){DZ();}//菜单
public static void DZ()//菜单
{
System.out.println("请选择：");
System.out.println(" 1.小学二年级口算题");
System.out.println(" 2.小学三年级口算题");
System.out.println(" 3.小学四年级口算题");
System.out.println(" 4.错题本");
xz=sc.nextInt();
if(xz==4) {CTB();}//错题本
else
{
System.out.println( "请输入题目总数：" );
n=sc.nextInt();
System.out.println("请输入数值的范围.");
min=sc.nextInt();
max=sc.nextInt();
switch(xz)
{
case 1:
while(max>100)
{
System.out.println("小学二年级操作数范围不超过100，请重新输入最大值：");
max=sc.nextInt();
}
c=1;
break;
case 2:
while(max>1000)
{
System.out.println("小学三年级操作数范围不超过1000，请重新输入最大值：");
max=sc.nextInt();
}
System.out.println( "输入操作数个数：" );
c=sc.nextInt()-1;
while(c>3)
{
System.out.println("小学三年级操作数不超过4个，请重新输入操作数个数：");
c=sc.nextInt()-1;
}
break;
case 3:
System.out.println( "输入操作数个数：" );
c=sc.nextInt()-1;
while(c>4)
{
System.out.println("小学四年级操作数不超过5个，请重新输入操作数个数：");
c=sc.nextInt()-1;
}
System.out.println( "是否有括号？是请输入1,否请输入0：" );
kh=sc.nextInt();
break;
}
System.out.println( "是否有乘除法？是请输入1,否请输入0：" );
cc=sc.nextInt();
TM();//题目
}
}
public static String Tm()//每题
{
Random r=new Random();
int sz;
String ch=null;
double a=r.nextInt(max)+min;
while(a>max){a=r.nextInt(max)+min;}
if(xz==1)
{
int b;
if(cc==0) {sz=r.nextInt(2);}
else{sz=r.nextInt(4);}//乘除法
b=r.nextInt(max)+min;
while(b>max){b=r.nextInt(max)+min;}
if(d[sz]=='/')
{
if(b==0){while(b==0||b>max) {b=r.nextInt(max)+min;}}//防止0为被除数
if(a%b!=0)
{
while(a%b!=0||a>max||b>max)
{
a=r.nextInt(max)+min;
b=r.nextInt(max)+min;
}
}
}
if(d[sz]=='-'&&b>a){while(b>a||b>max) {b=r.nextInt(max)+min;}}
ch=String.valueOf(a);
ch+=String.valueOf(d[sz]);
ch+=String.valueOf(b);
}
else
{
double[] b=new double[c];//操作数个数及数值范围
int k=-1,h=-1,z;//左括号，右括号
if(kh==1)//括号
{
z=r.nextInt(2);
if(z==1)//随机增加括号
{
k=r.nextInt(c-1);
if(k==0)//括号由开头起
{
ch=String.valueOf('(');
ch+=String.valueOf(a);
h=r.nextInt(c-1)+k+1;
while(h>c){h=r.nextInt(c-1)+k+1;}
}
if(k>0)//括号在式中
{
ch=String.valueOf(a);
h=r.nextInt(c)+k+1;
while(h>c){h=r.nextInt(c)+k+1;}
}
}
else{ch=String.valueOf(a);}
}
else{ch=String.valueOf(a);}
for(int i=0;i<c;i++)
{
if(cc==0) {sz=r.nextInt(2);}
else {sz=r.nextInt(4);}//乘除法
ch+=String.valueOf(d[sz]);
if(k>0&&i==k-1){ch+=String.valueOf('(');}
b[i]=r.nextInt(max)+min;
while(b[i]>max){b[i]=r.nextInt(max)+min;}
if(d[sz]=='/'&&b[i]==0){while(b[i]==0||b[i]>max) {b[i]=r.nextInt(max)+min;}}//防止0为被除数
ch+=String.valueOf(b[i]);
if(i==h-1){ch+=String.valueOf(')');}//补“）”
}
}
return ch;//以字符串形式定义算式
}
public static void TM()//总题
{
zts+=n;
int j=0;
String[] s=new String[n];
while(j<n)//制作题目
{
s[j]=Tm();
if(PC(j,s)==0)//是否重复
{
System.out.println((j+1)+"、"+s[j]+"=");
j++;
}
}
ScriptEngine se=new ScriptEngineManager().getEngineByName("JavaScript");
double[] sum=new double[n];
for(int i=0;i<n;i++)
{
try{sum[i]=(Double)se.eval(s[i]);}
catch(ScriptException e){e.printStackTrace();}
}//字符串转算式计算结果
DT(s,sum);//答题
}
public static int PC(int j,String[] s)//判重
{
for(int i=0;i<j;i++){if(s[i].equals(s[j])) {return 1;}}
return 0;
}
public static void DT(String[] s,double[] sum)//答题
{
int mint,yd=0,w=0,yn=0;//时间，已答题目，错题数，yes or no
double[] da=new double[n];//回答
int[] cwcs=new int[n];
double[] Da=new double[n];
double[] Sum=new double[n];
String[] Cw=new String[n];//错误题号
System.out.println( "请设置答题时间（分钟）");
mint=sc.nextInt();
System.out.println( "开始答题 ！");
long startTime=System.currentTimeMillis();
while((System.currentTimeMillis()-startTime)/1000<=mint*60)
{
da[yd]=sc.nextDouble();
yd++;
if(yd==n){break;}
}
if(yd!=n){System.out.println( "时间到！答题结束！");}
for(int i=0;i<n;i++)
{
if(da[i]!=sum[i])//判断答题对错
{
Cw[w]=s[i];
Da[w]=da[i];
Sum[w]=sum[i];
cwcs[w]=1;
w++;
zcts++;
}
}
try
{
File f=new File("CTB.txt");
try(FileWriter writer = new FileWriter(f,true);BufferedWriter out = new BufferedWriter(writer);)
{
for(int i=0;i<w;i++){out.write(Cw[i]+"="+Sum[i]+",共做错了"+cwcs[i]+"次。
");}
out.flush();
out.close();
}
}catch (IOException e) {e.printStackTrace();}
double cw=(double)(n-w)*100/n;//正确率
System.out.println( "你的正确率为 ：" +cw+"%");
System.out.println( "你的错题如下 ：");//错题
for(int i=0;i<w;i++){System.out.println((i+1)+"、"+Cw[i]+"="+Da[i]+" X"+" 正确答案:"+Sum[i]);}
do
{
System.out.println("请选择：");
System.out.println(" 1.再做一套题");
System.out.println(" 2.错题重练");
System.out.println(" 3.退出");
yn=sc.nextInt();
switch(yn)
{
case 1:
TM();
break;
case 2:
for(int i=0;i<w;i++)
{
System.out.println((i+1)+"、"+Cw[i]+"=");
da[i]=sc.nextDouble();
if(da[i]!=Sum[i])
{
cwcs[i]++;
System.out.println((i+1)+"、X 正确答案为："+Sum[i]);
try
{
File f=new File("CTB.txt");
BufferedReader in=new BufferedReader(new FileReader(f));
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(f,true)));
String line;
while ((line = in.readLine()) != null)
{
String[] tokens = line.split(",");
if(tokens[0].equals(Cw[i]+"="+Sum[i]))
{
out.println(line.replace(tokens[1], "共做错了"+cwcs[i]+"次。"));
}
}
in.close();
out.close();
}catch (IOException e) {e.printStackTrace();}
}
}
break;
case 3:
System.out.println( "你今天的正确率为 ：" +(zts-zcts)*100/zts+"%"+"
");
CTB();
break;
}
}while(yn!=3);
}
public static void CTB()//错题本
{
System.out.println(" 错题本 ");
try
{
File f=new File("CTB.txt");
InputStreamReader reader = new InputStreamReader(new FileInputStream(f));
BufferedReader br = new BufferedReader(reader);
String line;
while ((line = br.readLine()) != null){System.out.println(line);}
br.close();
}catch (IOException e) {e.printStackTrace();}
}
}
功能记录：
定制式题、四则运算及括号添加、年级的限定、错题记录及重练、多套试题的限时答题、错题本等。
问题无（主要是懒。。。）